Why would a guy donate his sperm knowing there could be legal repercussions down the road?

I dated a guy back in 2018 and he decided to help me try for a baby. This was done in Florida where a legal donation has to be done in a clinic. It wasn’t. We conceived my son naturally. Anyway, he had a girlfriend at the time, which I did not know about until I was 5 weeks pregnant! Once I found out I never saw him again. Why would a guy risk his relationship and have this potential legal cloud of me going after child support for 18 years! It blows my mind!

Btw, I’m not going to go after him for Chile support at all. Never my intention. Just curious why do that? Asking for opinions since I’m curious to know what you all think!