Join the club.  You've come to the right place.

I understand your fear. I dreaded telling BM about our upcoming pregnancy. I had a miscarriage two years ago and BM is so bitter that she actually laughed about it. She was never married to my DH and left him for her most current XH. Despite leaving, she is still obsessed with my DH and writes love letters to him.

Fortunately, my DH puts her in her place. He refuses to acknowledge her in any way. Please dont let BM or your Skids take this joy from you.  Just ignore them and enjoy it.

As a step parent you can step back or step out.You do not have to love or like stepkids, they are not your children. Its a bonus if that ever eventuates.   Take charge and make boundaries  if your health is affected than leave. Its really not worth the trouble, if your husband cares for you he can cut ties and move away with you..  Very often us women we take it all on our shoulders and try to fix the family, while husband stands around confused,  He had three children with the ex and that was their decision, not yours.let him deal with it. The ex needs counselling, perhaps suggest husband goes with her, so they can sort out the anger she is feeling and help her to except the situation.  Not so good to be angry about the money paid for support of his children, that is responsibility and he should be paying, not you not your problem..  As for quality time, it is important to the children, for their welfare and health. to see their father. they will grow up and time will calm things down.

 Most important is your welfare, do not get sucked into their negativity or problems,it will cause life long anxiety and illness and they will not care, put those boundaries in place and you will feel better its your life and it can be dealt with. Its  difficult  when a husband or wife leaves the family home and will cause deep bitterness in the mother, she feels betrayed and helpless and will take it out on her children against the father. leave him to deal with this as he caused the problem. Run if you can.

Any time I start to resent child support I think - would I still love him if he were in a job that paid what it does - minus the amount of CS. And yes, yes I would. He was paying that money before he met me. 

I know CS can be tough but the positive in this is that he's fulfilling his obligation and supporting his kids which is something that BM can't take away from him. I can relate to things getting tight and having to work the extra hours to try and make ends meet. Hang in there and don't allow anyone to take the joy of celebrating your little one that is on the way. Don't give BM, stepkids, etc. the satisfaction of seeing you unhappy. This is a happy time in your life and being bitter and resentful will take away from this wonderful experience.

Take a look at your finances and see if there are things you can cut down on like a cable bill, heat, water bill....whatever......and buget yourselves better. Although it may seem like it now the CS won't be forever.

Keep your head up!

Firstly, I definitely know how frustrating it is to be feeling the financial pinch from child support. We just got our order copy, and notice of impending earnings withholding (garnishment). Our BM, ToxicTroll, is getting a $30,000 severance for leaving her job, has money in teachers retirement account, and is getting 50K and change for a head injury she recieved at work 3 plus years ago. And we are still ordered to pay child support. And child stays with us more, too, requiring more food. And she wants us to take her places, and buy her things. IM like "ask your mother..."

But it is what it is, and its been determined as an obligation. Its still frustrating, I completely understand. The kiddos sound very entitled and ungrateful, plus with the parental alination going on, they are getting really messed up values. That whold "child of divorce" victimhood. Last night Munchkin SD12 tried telling a story and called herself "the victim", and I HAD to interject with "I prefer you not label yourselfa  victim, I suggest thinking of yourself as the bigger better person..." I dont think it registered. But her mother and older sister have become the consumate "victims", I am hopnig she doesnt fall down that rabbit hole!

And ex wives are exes FOR A REASON, and if there are children involved, it has to be a super good reason. My DH left his ex because she is a Toxic, abusive, alcoholic, pathalogical, narcissistic cheater. So guess what I have had to deal with for the past 4 years and 10 months? A really messed up bio mother who LOOKS for everything to be wrong that we are doing so she can blast us via text. Just when I think "well she cant get any lower", she does. She beat her eldest while the youngest watched and texted DH "oh well, at least she is 18 now and I cant get into trouble! tee hee."

So yes, the exes have to be horrible or we wouldnt be here on Steptalk venting our fears, frustrations and anger.

Enjoy your little peanut, what a gift! Who cares if others resent, cut them out of your life. Disengage. They dont matter in the Big Picture.