To add to what cat said, I believe (admittedly without a lot of proof) that in the long run standing up for yourself and your child will be seen as a positive by your H. Not now, but later. He will see that you did what was right for your family. And he'll know that means you would do what's right for him, when he is part of the family. It might piss him off now, but that is irrelevant. Do what needs to be done!
