You weren't trying to have kids but you were having sex? He didn't want another kid with mom #2 and he still had sex? He wasn't trapped into making babies. A woman can't do it on her own so blame her if you want to.
I despise it when people say that they have sex and don't think they can get pregnant. It is ALWAYS a possibility when you have sex. If you didn't want kids get fixed or stop having sex. DUH! Where were you in high school sex ed?
And it is HIS fault for not pursuing his rights earlier, that's what everyone has been saying. Your husband thinks he's going to waltz into a court room and pull this "I'm the dad" routine, it's not that simple. It's not in the best interests of the kids to be uprooted to go live with a man they don't know. At best your husband could get supervised visits.
It sounds like you guys are strapped for cash with your two missed pill accidents and you want custody to get out of support.
Sarah