SPOILER ALERT
He was actually sent to be used as some blood prostitute for a bunch of old ass men when he was 14 - this was because when he lost his virginity it was to some women who had broken up with her rich bf. This same bitch then signs a contract for him to be sent as a prostitute. He didn't like it obviously as it was against his will and they were doing whatever the fuck they wanted and it turns out that his current gfs father was one of the men their and he is afraid of him. Although the reason he was sent to such a disgusting place was because of the fact that after the gold digger left him when he was 14 she later wanted to go back to him but she saw him with another girl so she was like physco jealous. Anyway, he was practically emotionless since he was a child so there is that and the fact that he didn't particularly like or dislike anything, also shows that his current gf is very special to him although the things he does can't be justified fully he just doesn't necessarily understand why they are wrong so I don't get all the hate against him either.
If you're talking about the current love interest it's because when he was getting fucked up as a prostitute when he was 14 her father recieved a phone call from her and she hoped for everyone around him to be happy or smt and he was deeply attached to those words as he saw them as a sort of hope and when he met her he knew he wanted to be her boyfriend but if we're talking about the backstabbing bitch then she was just the first person to teach him how to have sex there wasn't really any attachment
I assume this guy has some trauma that has made him such a fucked up cheater/slutboy.
I guess we'll eventually find out.
Meanwhile, damn, he needs a keeper. And that girl needs to RUN FAST away from this dude.