It was purposely made so you couldn't attend. I'd be telling SD to reimburse the money you put forth. 

The wedding rules were purposely designed to make it difficult for you.  Tell them you want the money back and don't go. 

She did it on purpose. That's really ugly of her especially after you financially contributed. I think you should ask for the money back since you and your children are obviously not welcome and then take your kids on a little vacation. If she doesn't want to reimburse you then I would just show up with the kids. Then again I am petty like that. Just play dumb "oh I thought it was directed at your friend's not your direct family"

I think your wife is being awfully inconsiderate. Just because it's your wedding day doesn't mean you can treat people like crap. As a parent I will always support my children but I will not support sh***y behavior. She should be the one to set her straight. It's just two 10 year olds. Assuming they are well behaved, there should be no problem. It's not like you're asking to bring the whole 5th grade class.

Fun story: My husband's cousin did this. She invited over 250 guests to her wedding. A month after she got back the rsvps she sent out a note saying anyone under 15 could not attend. She asked everyone to respect her wishes as it was her wedding day. Guess how many people showed up to the grand ball room? 28.

When did the age limit come up?  Are there other friends and family members with kids that will also be excluded?

I mean, not having children attend weddings is a "thing" that some wedding couples decide on.  Whether they feel that kids will be a distraction.. or whether they feel it will hamper the adult "fun"..   And there is some difference between a 10 year old and 14 year old.  Child vs teen so to speak.  

And when faced with these kinds of situations, a general wedding guest would need to decide whether to attend, miss the event.. get a baby sitter.. switch custody weekends.. etc... but in your position, I can understand being upset.. especially if this age issue came up well after you had contributed money of your own to her party.

So, I might approach it this way.  First, do you believe your two children would be able to attend, behave and need no special accomodations.. would eat the food happily (not require a special kid meal)  and basically be the "seen and not heard" type of child guest?  Would you be willing to do something like compromise and sit with them at dinner and then take them to the hotel after that... letting the "real festivities" drinking and dancing go on after you had left with them?  If you honestly can say that your two kids would behave perfectly and be good guests.. I  might get your wife to lobby for allowing them to stay for the meal and leave after that.  If that is not possible then you have to decide how big of a hill this is for you... Do you want your money back? could you even get it (knowing your wife wouldn't probably want to do that).. Would you just not attend period?  Is there a possibility that you could switch a custody weekend and would you do that so you could attend with your wife? 

In the end, it's a tough situation.. the money is spent and you probably have a better idea of the likelihood of getting any of it from this person.  I would guess about close to zero.  So, that leaves you to think about whether attending is even something you want to do.  I'm not saying that either way is wrong.. certainly reasons for attending and not attending.. your wife likely has her own thoughts as well.  In the end, while your kids may need to spend a night with a sitter.. it's not like you would be giving up all your time with them.. just a few hours.. but I can see the principle of it being hard to get past.

I would stop being so readily available to SD with your time and money.  She can get that from other sources, such as her mother, fiance, extended family.  She can't have it both ways (you are good enough for car services and cash, but not for her to be polite to).  

As for the reception thing, I would ask your DW if this age limit thing is only extended to your children, or to all children under 14?  I would also ask your BM how she would feel if the roles were reversed and it were your daughter limiting DW's interactions and ultimatly shunning her from her reception.   I would also ask her if this is going to set a precedence going forward for all other children's weddings?  Where you will be required to pony up the money, but sit down and shut up when it comes to being treated like an outsider and dismissed from the wedding.  Ask your DW if she will be okay when you allow your own children to treat her the same way when it comes to their wedding days?  I would also recommend some couples counseling for you and DW going forward as you have a very large family to try and blend.

So age limits don't effect brothers and sisters. In a wedding   Your kids are not guest they are family. 

wedding he is not allowed to attend. This, after putting funds toward her wedding. I'm not insinuating because of his contribution he bought his ticket to the wedding, however, if SD doesn't like him or has contempt for him, she should have the common courtesy not to use him and his money for HER WEDDING.

The wife's response is very troubling and telling. She's clearly putting DH on the back burner, and they are pretty much newlyweds themselves, being married just under 2 years.

I wouldn't want to go where I'm not wanted. I would just send the wife and tell her to have a good time, and do something with MY KIDS during the week-end visitation I had them.

I'd elect to just stay home.  Then i would #neverforget and COMPLETELY disengage from her.  

Then I would stew in my resentfulness toward my partner over their unwillingness to back me up...then eventually divorce.

(not saying that my method is right....I'm just very stubborn).

This adult skids hates you, but happily uses you. And your wife is condoning it. Niiice.

OP, is your wife older than you, or did she start having kids at a very young age?  If she is older, could it be she thinks that gives her the upper hand in your marriage? You haven't been married very long, but she sure seems to expect you to hand over your wallet and do as you're told. We teach people how to treat us, so why have you spent ANY money on this hateful witch your wife spawned? Did your wife manipulate you?

I think it was a mistake to join finances. You each have three minor children to support, and given how much you've already spent on her eldest and how poorly you're being treated, I'd immediately cut off access to your money and credit. If your wife thinks quality men willing to accept disrespect and subsidize women with broods of kids are thick upon the ground, she's quite mistaken. This is an eye-opening point in your short relationship. As Miss Texas points out, you'll still be expected to fund lodging, travel, meals, clothing etc so put your foot down NOW. Either your kids attend, or you don't and you expect to be reimbursed by the rude couple immediately. 

Please stick around the site and do some reading. You'll learn that finances need to be handled very differently in second marriages. You support your kids, she supports hers, and you each contribute an appropriate percentage to the monthly household costs. Your wife has a lot of kids, but it's NOT your responsibility to support any of them. In fact, when you spend on hers, you take away from your own. Please take a hard look at your relationship; is it an equal partnership? In steplife, people who don't stand up for themselves get ran over, and you've got tire tracks on your face.

Your SD is an ungrateful little snob. With a Mother who can't tell her that your daughters, her SD's are coming to the wedding and that is that.Shame on your wife for not having your back. I don't care if this SD hates you, so what. Weddings are family affairs and your girls are family. It is called etiquette. Your wife needs to tell your SD this. All weddings have people they don't want to invite but do because it is the right thing to do. Your SD is an entitled young woman who has many things to learn in her future. She had zero problem taking your money.  Oh karma is heading her way. I feel sorry for this poor guy she is going to have a future with. I think the real problem is between you and your wife though. She seems to go along with this Bridezilla.

Fuck that.  You are paying, anyone you want there goes.  Take your kids to the wedding and reception and seat them where you want them.  She can either STFU or you  threaten to loudly demand repayment of your investment in the wedding or reception.  Whisper that part in her ear if she so much as frowns about your children being at the wedding and receoption.

Rent the nicest suite at the venue so if your younger kids get tired they can get some rest while you, your older kids, and your wife are all conspicuously front and center.

The bitch SD won't give the money back, you can guarantee that!

Go to the wedding that you have paid a large sum of money towards, take your children, and participate fully in every part of it.

If bitch SD or your disloyal wife, say anything at the wedding about your kids being there, tell them to STFU or you are going to stand up and speak to everyone there about how they took YOUR money but didn't want your children there...

Pretty much what Rags said, lol