Uhhh....the answer is no.

You should have never done it.

DO not do that again. I dont care if she is the Queen of Oz.

No mama, no baby! 

The right thing is for your partner to set her straight. Do not let this continue, please. If it does, imagine what your child will think when they get older. 

What reason/s does she give her father for having no desire to meet you?  

Who was his visiting the area daughter staying with that he just left you sitting out in the vehicle? I really hope you don't answer your future MIL. 

No matter what article, blog, forum, etc. I read- this is always such a touchy subject (the subject of half siblings and their relationship amongst themselves and with their respective parents). 

I think peoples' opinions are formed based on their own experiences, for sure.  For example, if you're a half sibling yourself, your opinion will be different from someone who isn't, and so on.  I am NOT a half sibling- I am a step sibling, but my biological children have two half siblings.  So my opinion will be based on what I've experienced in that situation. 

My children and step children are well aware that they are half-siblings- my SKs are several years older anyway, and realize that they don't have the same Moms.  They don't even have close to the same lives, really.  They are very different, though they do share the same father.  I don't go around always saying "your brother," "your sister," etc.- they call each other by their names.  Although I don't hinder a relationship between them by any means, I certainly don't push anything either.  I want them to foster their own relationship and feelings for each other without it being forced.  There is so much difference between them and their lives that it's OK with me that they aren't super close. 

SK's personalities, manners and lifestyle as a whole are not acceptable to me or my family (such as when they first met my mother and laughed and called her weird to her face- for no apparent reason, which hurt her feelings; telling people that they are better than them, strong, prettier, etc; snickering at others and making fun of basically everyone, bullying, etc.).  Heck no I don't want my children growing up influenced by their "brother" and "sister!" Another poster on another thread also said that they don't always like how it can be off-putting to the non-similar parent, and I agree.  My SK's aren't my kids (let's not get into anything other than biology here), although they are half-siblings to my children.  I don't go around shouting to the world that they are all brothers and sisters, and that's OK!  My step children don't go around shouting that I am their "mother," either.  They make sure that "step" is always included before, if they refer to me at all, so why isn't it OK for me to include "half," or "step" when referring about them, too?  I know this will provoke different reactions and feelings, but it's just an example of how divided people are based on personal opinion or experiences on similar issues. 

If my step children told their father that they wanted a relationship with my children, but nothing to do with me, that thought would never make it off the ground into a tangible idea. 

That is NOT acceptable- do not ever put yourself in a situation like that, you are worth so much more as a person and as a mother.  Too many times I hear about (and have experienced myself a couple times before I started speaking up) the step-parent being cast aside and not always included as part of the family. 

You ARE part of the family- you are the matriarch, even, of the family you created with your soon to be husband.  Step daughter may have been created from a previous relationship, but that does not mean you are coming into Dad and SD's family- you have created a new family, and everyone is coming in together.  In our family, there is no "well they were here first" kind of talk.  If SD does not want to be a part of the family, then that is her issue.  You are NOT going to be isolated from your family.  Don't let her have that power, because it's not hers to have in the first place. 

I do not really take age into account with the way people think- maturity as a whole, experience and so many other factors come into play - I have seen mature and understanding 12 year olds that are more compassionate than 33 year olds.  So her being 18 years old is irrelevant to me in my opinion of her and her behavior. Which in a nutshell my opinion isn't a very positive one.  I would totally understand if you were wary of a relationship between her and your child.  What's going to happen when they are older?  How is she going to talk about you towards your child?  I would not want my step children disrespecting me or speaking ill of me towards my children, or trying to weaken the relationship between us.  Which seems to be already happening by the SD only wanting to see your child- in some respects, you and your child are a package deal!  Are you supposed to sit out of Christmas dinners?  Not attend birthdays? 

Dad should have also never let that situation happen- there's a difference between catering to SD's wishes and catering to the family as a whole.  If he is walking on egg shells around his daughter and seems to be wrapped up in other priorities besides respecting you as a mother and wife, then you may need to post pone the wedding or re-think it entirely.  Don't get stuck in a toxic relationship where you are on the back burner and SD is basically calling all the shots.  Dont' let her isolate you in your own home with your own family, and certainly don't let your child be influenced by her.  What exactly is happening when you aren't around, too? 

Where I am going with this is my own step children can be a little passive aggressive towards my children, and I've caught them a couple times.  One time SS hurled a basketball at my oldest, which narrowly missed him (hes 2).  It was supposedly "an accident," and I was the only one who witnessed it.  But I know exactly what the intention was; another time the step children were rough housing and throwing the living room pillows around, getting our large dog (90 lbs) riled up.  I asked them to please settle, as the babies were in the room trying to play around as well, and I didn't want the dog to trample them.  Well, as soon as I went into the kitchen (but my eyes were still watching, unbeknownst to SKs), SS intentionally threw the pillow right at my son, knowing the dog was going to leap for it, causing the dog to basically land on my son.  He was hurt, thankfully not bad, but I was so pissed.  I went in and lost my cool, yelling and cursing at my step son.  Dad didn't really take it seriously, because he didn't see it and can't fathom his child(ren) doing anything like that.  However, I know, and I'm very wary about it- another reason (not related to your post, sorry, not trying to make this about me!) that I sometimes have reservations about leaving the relationship I'm in, because I'm terrified of Dad having custody and my children being in SK's company without me. 

Anyway, you can't trust anybody anymore in today's world.  With your child being so young, there's no reason you shouldn't be included anyway.  And, if you do go through with the wedding, you are the step mom!  SD needs to find her big girl panties.  There's lots of crappy things in life, and we need to get over it!  I'm so tired of hearing all the time about people catering to the childrens' wants (notice I did not say "needs," because that's different) in divorce situations to the point that they become entitled, disillusioned, and just as clueless about life as all those kids that get "participation" trophies in everything and never experience what it's like to actually lose (which happens in life, too!)  Before anyone gets their feathers ruffled, I'm not referring to extreme cases where children are neglected or having serious physical or emotional harm at the hands of others.  SD needs to realize what she's requesting is just absurd. 

It sounds like she isn't routinely part of the family anyway if she's just coming to visit, so she can suck it up sometimes and even if you and her don't have a fuzzy, warm loving relationship, she can deal with it if she wants to visit.  I am glad she wants to have somewhat of a relationship with her HALF sibling, but if she does, then she should respect the fact that you are the mother, her step mother, and part of her family whether she likes it or not.  Don't let anyone dictate what your role is going to be or where your child is going to be shuffled off to when SD is around. 

Stay firm, mom!  And since you didn't when SD had already visited, from this point on, speak up and stay strong!  If Dad can't handle it and is more worried about SDs feelings than yours, then like I said before, don't get married yet!  Work through the issues- I never married Dad because we had issues we can't iron out, and still can't iron out.  If it doesn't work out in the future between the two of you, being married is just going to bring a whole host of other problems to work out when ending the relationship.  I'm not saying I want this to happen to you- I hope you have a long, happy healthy marriage and you and SD work things out and have a very functional family; but, I'm just talking through experience and what, unfortunately, is a reality for a lot of people in step-families.  Thanks for reading this!  Good luck!

See, this is where I think the dad can really BE a dad and encourage SD to meet you because it IS the right thing to do. He can give the speech about how you will be one more ally in her arsenal, how you make him so happy and he'd love to share you with her and her with you. He could do the old, "Let's just give it a try once and see how it goes. I bet you'll find something to like about SM."

If she's still resistant, he could say, "SM is very special in my life and I don't want my life to be in two parts -- your part and SM's part -- so I just really need you to give her a fair shake. I'm not asking for you to be anything but polite."

As long as he indulges her demand that you be left behind, there's no chance of civility now or later. And trust me, how things are handled right now will affect the rest of your life with this man -- I've been married 10 years and we're still fighting about how my husband handled things early on with SD because how things were handled early on has set the pace since. My SD was allowed to call the shots and decide when SHE wanted to meet me. It has not gone well since and that was 20 years ago.

You do not get to do over these early days, so do what you must to get him, them, to do what would be expected in any other type of relationship (we meet our husband's friends, parents, co-workers, so we should at least meet their kids when we're dating.) If he won't give in, if he won't put your comfort on the same level as SD's, think long and hard about this relationship. It does not get easier.

Do you want someone in your child’s life who basically is going to give them the message that their mother is a POS?

i think my SS34 and his GF are disgusting aholes.  They would be idiots (okay they probably are) to send their child to spend time with me.  I’m ok with that.   “Welcome little child - your mommy and daddy aren’t allowed near me because they are bad people “.  That would be wrong even if it was only implied not explicitly stated. 

So you have to be concerned about HER comfort (she is an adult), but she clearly has zero concern for your CHILD’s comfort level. How exactly does she or your FDH think that your child is going to feel about her only being able to see her sister if her mom isn’t present (without any  reason).  You are an intact family and a package deal for this adult to either accept or move along.  I can see her not wanting to FaceTime with you- but to refuse to meet you is weird.... and your kid will think so too in a couple years. 

It would be different if you weren’t together and could be explained- what will your child think of her father for allowing this? What does this teach your child (or this young adult for that matter) about relationships and marriage?? What will they tolerate in theirs if this is allowed? 

No only no, but hell no.   SD gets to see your child only in YOUR presence. If DH had a problem with this... find a new DH.  He can then fit face time between his youngest and eldest into his limited visitation time.

Why would you tolerate this toxic Skid interfacing with your young child except under your direct supervistion?

I wouldn't if I were you.