He doesn't take sex as an autonomous actions of pleasure but a job. So he for long didn't care if it happens consensually or not. Just like we take orders from out boss for jobs we don't want to do. It is technically violation of our boundaries but we endure it. Same with him.
However after he fell in love and realised sex was infact an act of passion and love or at least an act you do with people you like with consent he resisted.
This is very sad but it shows the lack of self respect and preservation and attitude towards sex as an act also lack of boundaries. In real world you go to psychiatrist and therapists to work on this but it's manga so....
He doesn't take sex as an autonomous actions of pleasure but a job. So he for long didn't care if it happens consensually or not. Just like we take orders from out boss for jobs we don't want to do. It is technically violation of our boundaries but we endure it. Same with him.
However after he fell in love and realised sex was infact an act of passion and love or at least an act you do with people you like with consent he resisted.
This is very sad but it shows the lack of self respect and preservation and attitude towards sex as an act also lack of boundaries. In real world you go to psychiatrist and therapists to work on this but it's manga so....