Wasn't sure where to put this. It's more of a 'what should I do?' than an 'AIBU?'.
Backstory
I had only known EXDP for a few weeks when I got pg. We were knowingly having unprotected sex. I told him I was broody, in fact I tried to break up with him because I said I wanted kids soon and he was v young (18). I suggested condoms to him, but he refused to use them. I thought we would probably be safe because we only had sex during the 'safe' parts of my cycle but that didn't work. I told him in advance that if I got pg I wouldn't have an abortion.
He seemed happy at first when I told him the inevitable news. He bought a flat (his intention anyway) and I moved in. Our relationship became more like 'friends who slept together', we weren't in love and didn't want to be a long term couple. The plan was for me and the baby to stay at his until the baby was a few months old and I had found a job and my own place.
Then, out of the blue, at 39 weeks pg he said he had changed his mind about becoming a dad and I had to move out immediately. I managed to get a flat in a pretty scummy area 10 min walk from his. I called him when I was in labour but he didn't come to the hospital because he was 'too busy'. I called again after the birth (when still in hospital) and invited him to see his DS. Again he was 'too busy'. He knew my new address and phone number and said he would call later that week to arrange a visit. That was 8 years ago. He never came to register the birth so has no parental rights and doesn't even know his DS's name.
When DS was 2 I met DP and we have since had a DD. DP is great with DS and treats him like his own, although he doesn't get called dad. (he says he would if we got married)
I've never tried to chase EXDP for maintenance because firstly, I wanted to make a clean break and have nothing more to do with him. I managed to support DS financially myself (I had a well paid f/t job before having DD). I really wouldn't want DS to ever have any contact with EXDP. I know that legally, paying maintenance wouldnt give him parental rights but he might try to do it out of spite and I haven't wanted to take the risk. Also EXDP has spent most of the past few years working abroad so I couldn't have got maintenace from him anyway.
However, now I have found out that he has set up a successful business. I imagine that he is making a fair bit of profit. Being self-employed he would probably try to 'hide' his income (knowing him) so it would probably be fruitless but should I now try to chase him for child support?
Morally I feel that he owes me but I dont want to bring a negative influence into DS's life. (I would fight him in court of he tried for access).
Should I let sleeping dogs lie?