So sorry that this situation is evolving in the manner that it is evolving. It is not likely that your husband is going to take any action before the birth of your next child. It may be that he has had conversations or a good sense of how the older children would feel or respond to the the return of his daughter.
You will do what you feel compelled to do and he will probably fell compelled to do the same.
If you are thinking about court, if he has been awarded visitation, the court is not going to rescind his visitation. If the mother is willing to agree to his having full custody, the court will award him full custody.
A judge is not likely to say that a child should be banned from a home for something that the court or the mental health system would not have removed her from the home for those particular actions. . I have never heard of courts support removal or banning a child except for the most extreme situations.
If the 2 of you separate, the court will without doubt award some amount of visitation to your husband; there will be no way to avoid your step daughter having contact with at least 2 of your children.
Separation and divorce will only ensure that you no longer need have contact with your step daughter.
If this ends up in a court, the court will not be looking at this through the lens of angry and supportive SMs.The court will be looking through the lens of the law and the best interest of the child.
Both you and your husband should take a deep breath and rethink your particular next steps.
Are you prepared for and capable of being a single parent of 4 children? Is he capable of and ready to become the single parent of 3 children? Is this what either of you want, because it is where you all seem to be headed.
An honest assessment would suggest that he may be in the better position to be a single parent , as without you in the picture, his parents might step up to help him with child care .
These may not be the things that you wish to focus on but these are the realities that you will be facing. Real life and legal realities may not be the same as internet consensus.
There is still time for you and your husband to seek family.counseling.
You are not likely going to prevail in keeping the child out of your home , and a court is not likely going to care what she said as a 12 year old particularly if they would not have deemed that to be grounds to remove or ban her from the home..
Focusing on the here and now and moving forward will be impetus for the courts. A 15 year old with a SP who has not seen or interacted with her in 3 years and a biological mother with hea!th issues (even though those issues may or may not be terminal) is going to be a child that the courts will be inclined to ensure that she has whatever housing arrangements to which the biological parents agree. The courts will likely suggest or require therapy for the daughter and counseling for the family.
Now might be the time to begin making your decisions based more on advice from a solicitor or attorney and less on consensus input.
Your baby will be fine. Babies all over the world are born to mothers in stressful situations and manage to do well. Your 2nd child seemingly managed well inspite of the PND that your experienced during your pregnancy with him.
Please, no matter how this situation is resolved, try to get counseling for yourself and your family.
If you believe in prayer, this might be a good time to make the Serenity Prayer your new mantra.
May God keep all of you in His loving care.