Adoption when other parent is MIA

I have a question. My child is almost 5 and knows my husband as DAD. The bio father hasn’t attempted to make contact since our child was about 2, when his new wife basically told me to stop. (I was the one foolishly wanting to keep them updated on my child when they didnt even want to be!) Back story: I got on a plane with our shared child when he was 3 months old. He didn’t fight me on it but his parents sure were mad. Am I going to have to be able to locate the bio dad for my husband to be able to adopt my child? Or does this fall somewhere in the lines of abandonment? What happens if I can’t locate the guy to even serve him? Do you think his family will make a move if they saw he was being asked to terminate rights? Can i go through adoption without his consent if he and his wife literally want nothing to do with my kid?