She wants us to get my Husbands child 50/50 but still wants child support-- What to do?

So, my husband had a fling with a girl and she became pregnant. She was cheating on him, and he made her move out, and she told him the child was the other guys-- who she is with now. Well, we got tired of hearing the child looked like my husband so we had a paternity test done, and it was his. Let me jsut say that I was 8 months pregnant when we found out my husband had a 5 month old. We pay our child support-- we have it automatically deducted from my husbands pay check-- we cover medical, we cover co pays!! So, here is the situation!! She is pregnant with her 4th child, each with different dads!! She told my husband she didn