My husband is stuck in the middle of this. He wants me to basically hide the rest of this pregnancy. No updates, no one can talk about it, no setting up the nursery, and to hide all the baby stuff when SD visits.

Your husband is an idiot. Will you be expected to hide the baby, too?

Tiptoeing around SD in not going to cut it.

Considering the fact that you have 3 other children and she is 14 he shouldn't be coddling her like this. Now you have another on the way. Lucky for me this actually one problem I don't have. SD and my kids have a good relationship she's not jealous of them. But trust me every other problem you can think of we have. I've come to the conclusion that these families don't work. I read your post and because of her mother and her behavior I think you will be miserable for a long time. I wouldn't even waste my energy and just focus on your kids. I had to do this but it did slap me in the face because my H constantly accused me of being heartless for disengaging but even with that I told him I'm sorry I can't do it anymore. My biggest regret in life was not having a family of my own. Is there any way you can get away for a bit, go see a friend for dinner. Between his job and all the work he's putting in to earn back his daughter is he even around to give you a break?? Having 3 kids of your own and being pregnant can really take toll on you. I only have 2 but one of my kids is special needs. I'm so tired I don't have the energy for anything else and it's hard when you have a BM constantly needing needing needing or causing issues in your household. You have no privacy no life of your own. I look forward to when the quarantine is over and things go back to normal. I don't things are going to change anytime soon and you have a lot of kids to care for. Any way you can see a therapist or talk to someone. I'm sad to say you might not be able to talk to your husband because he's too busy feeling guilty. I have often felt that I'm alone here. My H provides us with a roof and food but I can tell you most definitely my SD is his first priority. 
The fact that your husband wants you the hide the pregnancy really speaks loud to me. You see where his priorities are. Please stay healthy and focus on your kids it's not healthy for them either.

Your SD is being alienated by her mother - every thing you've described as "her" feelings are coming straight from her mother. It's her mother who is jealous that you are having a girl, not SD.

This is unlikely to get better until SD is old enough to start thinking for herself, which is a long time from now. Does your husband plan to dress the baby as a boy so that SD doesn't get mad?

Walking on eggshells around SD isn't the answer to the problem. Your DH has to keep being the best parent he can be to her under the circumstances, but I would expect she will cut off contact with him soon.

What a bizarre situation!  Everyone except you seems to be colluding with SD14's behaviour, and implying that it is OK.  It is emphatically not.  SD14 sounds frankly, disturbed, and probably does indeed need therapy, but not because you are "ruining her life" but because she is suffering from delusions about the situation, which her father is reinforcing. 

My SD was 18 and not a part of my family when she found out I was expecting a girl. All 7 of her cousins are boys. I was about 5 months along when she found out because it took that long between me falling pregnant and DH managing to meet up with her (she only came around for christmas/birthdays to collect presents). After wanting nothing to do with the dad that she tossed aside for years, she burst into tears in the middle of dinner and fled the restaurant. BM exploded at DH saying how he doesn't care about his daughter and now he's traumatised her for life. 
My DD has never met her half sibling and with the current dynamic I have no plans to introduce them. I'm ok with that. I don't splatter my social media with photos of DD but I do put stuff up only for friends to see. Otherwise what's our other option? How long are you supposed to hide away a human being? Do we pretend that we don't have a toddler to appease an adult child that hates our guts? That'd leave our DHs with two messed up daughters instead of just one!

Then his ex calls about a few weeks later to tell us that she had to take her to the doctor and now SD is in intensive therapy because I am having a girl.

Has anyone (SD, therapist, BM) asked DH to participate in a therapy session?  If no, does DH even know the name of the therapist? If he does, he should reach out to the therapist and state that he is willing to meet with the therapist so that she has a complete picture as SD undergoes treatment. 

Since the problem, according to BM, all stems from DH, it would seem.odd to me that the therapist has not spoken to dad.

Has your husband talked to her therapist? Or is it all going through BM? I doubt a therapist would suggest hiding a pregnancy and baby or rewarding rude behavior with multiple solo trips a week with Dad when he has 3/4 other kids and she needs to start accepting she is not an only child/daughter. 

This girl needs her Dad to step up and start parenting rather than coddling. Is there any chance that he would take a parenting class?

All baby things hidden for when princess precious comes over. 

The bigger question of hypocrisy here is why could bio mum have more kids with no princess precious chucking a massive tantrum. Why give her the power to control your marriage narrative??

my husband despite all the skid and crazy exwife issues is very firm on that my and hubby’s sexual/intimate relationship is between the 2 of us. The fact we are sexually active, the fact we choose to have more kids is not any of skids business. If i am pregnant, skids are told  when i am several months along when it’s starting to show i am pregnant. 

They do not get to tell hubby he shouldn’t have more kids or they fee sad and rejected and believe me my skids have played that game which is total bs. Because everytime hubby tries to catch up with them or contact them its always “i’m busy!!” Then something major happens like me and hubby travelling with our 2 young kids overseas or buying a house and its a sudden sob story hubby abandoned them blah blah blah. They demand one on one holidays away expecting hubby to leave me at home with 2 toddlers for a week.

my husband is firm that me and our 2 kids are his family too and hubby wants us on all holidays so a holiday for just skids and him just will never happen

if things are this bad for op, what happens when you are in labor and need to go to hospital, is princess precious gonna chuck a tantrum and demand daddy have 1 on 1 time pronto and stepmum can eff off to hospital on her own?? Of course not!! Its time op husband grows a pair of balls and sets things straight. Its horrible that sd is already trying to erase a sibling from existing before she is even born.

instead of being a big sister to set a good example to her little sister she is instead setting an example for how not to be a good pleasant person...

You run your home, if SD shows up, she must respect you. If she doesn't show up, it's her lost.  But you must STOP playing her game. Love you one day, hate you the next day 

You problem is you have a HCBM. She is bitter about DH moving on and being happy. If she can't have him, no one should.  Her underlying motives are his misery.  SD is just a pawn.    Having gone thru a high conflict alienating BM and having an ours baby, it's not fair that you have to put up with all this drama when you least need it.  I would recommend DH seeing his daughter away from home for now. Stop coddling her. Protecting her from reality will not help her grow up.  DH also should make it clear to BM that he divorced HER and not SD, that he has enough room in his heart for all his kids.  Even so, he still might end up losing SD to BM.   Chasing after her will only empty his wallet and steal time away from people who truly care about him.  My DH lost 3 of 4 skid to BM and her dysfunctional practices.   You most certainly don't want your daughter growing up watching her father chase after SD and ignoring her. 
Your home is your sanctuary, as such only friends of the marriage and family should be welcomed in with behavior that supports it, not tears is apart. 
Sometimes dropping the rope and giving BM what she wants is the only way to get out of the fight.  It's a last resort move but one that many around here eventually choose.  It's a part of reclaiming the role of adult and director of your own life. Men seem to have a problem doing that.  Stepmoms here get there faster, wore out from the drama. 

I'm afraid I'd probably decide to rub the dear child's nose in it by taking absolute high-visibility JOY in my pregnancy and making it known! Better still, take her with you occasionally to buy baby things and tell your DuH that you're helping her bond with her new sibling, making her feel more of a part of your family (evil grin).

Okay DH, good plan there chachi. Seriously, nothing like coddling the poor little SD because her feelings are hurt. Does she not understand how kids are made; that you have no control over the sex of the child? Oy. 

I would not be catering to SD over this, not at all. 

Is SD dense?  Does she not comprehend that her mother has already replaced her twice with two younger sisters?

Your DH is catering to, facilitating and enabling this crap.  Time for this little hag to learn about a life of abject misery until she extricates her head from her butt and knocks if her pathetic toxic manipulative toddler tantrum crap.  Rather than hide your pregnancy and baby girl I would be celebrating it, broadcasting it and rubbing her toxic nose in it.

That your DH is coding this crap from this kid is pathetic.

Start mailing her weekly pink girly event cards touting her upcoming status of being a big sis to another baby girl.

Her manipulative torturous behavioral crap is pathetic.

smh

You deliberately conceived a daughter? Wow! *ROFL* How did you manage that?

SD is behaving this way because all of the adults in her life are permitting her to do so. 

Celebrate your baby girl - congratulations!!

My formerSO's kid13 was jealous of our baby. He tried to hurt him. Multiple times. Of course daddeee stayed blind or made excuse for the behavior. I left to keep baby safe.

Keep a watchful eye out. 

Your husband needs an intervention. Who are the people that he respects and listens to? 

I have the issue of my sd9 reporting everything that happens in my house back to mil and bm every week. Dh and I have adjusted our lives so that we do not talk about our life or any business in front of sd9 nor do we share any news with her. I just put one of my cats down last week and I waited for her to ask where the cat was before telling her. Since she is a spy and has chosen to work for the opposing team she is not privy to anything about our lives.

Dh and I talk weather, politics and sports amoungst ourselves when she is here and talk business and personal things when she is not here. I also do not take her anywhere and neither does dh bacause we will not give her a gossip supply to talk about to the other household. She does the same routine when she is here every time. 
 

This has helped immensely with the gossip. It's her own fault. Perhaps taking this route would work for you too. Good luck!