Don't deal with your husband or OW, just go through your attorney.
Personally.... for child support reasons (and I could be wrong, but your attorney could clarify this)... I would probably try to get the D through as quickly as possible. Until the baby is born he does not have other biological children he needs to support. I'm not familiar with state or federal laws on this but it may be that until it's born, it's not a "viable" child yet.
You may want to ask your attorney about these things... Can an unborn child be factored-in on current child support? Once it's born how would that affect your child support? What if he isn't the biological father? You might want proof of paternity addressed.
Don't ask your husband any more questions, don't call him about court dates, Don't talk with him or OW directly about the divorce (especially don't discuss any divorce details or stategies with them!!!), and stop thinking about his life. Just take care of you and your kids.
There is no arriving, ever. It is all a continual becoming.
