wait, what nasty thing did tom riddle sr. do? i'm not exactly fond of stuck-up rich people, but being stuck-up and rich isn't like, something he did on purpose just to spite merope. he was just hanging out being a rich muggle who was kind of a dick, and then he got raped for like a year or so, and then when he was no longer under merope's magical control, he ran off because, you know, he was BEING RAPED. and then he tried to go back to his old life, but obviously things never quite went back to normal since when he died he was still living with his parents and apparently no longer had a fiancee.

imo, he had no responsibility towards his son, since he obviously did not consent to sex, and he may or may not have even known merope was pregnant.

rape victims do not owe their rapists ANYTHING, no matter how pitiful they are.