What would you do?(Advice)

So for the past year and a half my husband has been verbally and physically abusive, he's also been cheating. Just recently I went home to visit family and needless to say I cheated on him. Now I'm pregnant and I know it's not my husbands. I cant decide if I should keep the baby, do adoption or get an abortion. I don't think that my husband can have more children (we have a 4 yr old) so I thought we could keep it and he could raise it as his own. He's not having that. The sperm donor doesn't want anyone to raise his child but he's in and out of trouble with the law. I really don't want an abortion, if anything I'd do adoption. But it's either have an abortion or lose my family. Advice please?