you're absolutely right. to him it's a mess he wants to sweep under the rug.It seems like he thinks of his daughter and her mother as a unit. She was part of his "troubled past" so he'll punish her by extension. If the mom was THAT adamant about him not being involved or even seeing her and he wasn't interested, would a judge have really given him partial custody? Idk how the system works but that seems really weird. If I had to guess, maybe he caused a stink about getting custody and getting involved in her life but then never followed through and ghosted.
my guess, complete conjecture and could be totally wrong, is that she didn't tell him in the first place because she remembered him as being married (or separated at the time, but still, he had a wife and kid in another state), and also had whatever brush with the law that happened at the same time, so he clearly wasn't in a great place in his life, and that's why she didn't contact him earlier in the child's life. once paternity was established I'm guessing it was an arrangement where she said if he wanted a relationship they could pursue that (otherwise why wouldn't she specifically request full custody? why would he be allowed legal visitation?) but by that point he was already back in his marriage, had Abbie - would she have been in the early stages of being diagnosed at that time? I can't remember how old she was - and just wanted the whole thing to just disappear. they weren't part of his family unit that he had committed himself to by this point. it was easier to just pay the payments and not think about it, or them, any further.