A serial cheater who doesn't have an ounce of self control. This guy cheats on his girlfriend by chapter 2 and he's cheating from that point on, no matter who he's dating. He breaks up with his girlfriend because he wants a more physical relationship and she doesn't. I don't really have an issue with this part. He gets a new girlfriend who is ready for the same level of intimacy and immediately cheats on her when his ex makes a move on him.

I'd be fine with this if we were just following a scumbag MC, but it seems like he's supposed to be more on the side of indecisive and weak-willed. In chapter 12 it reach a ridiculous level in my opinion. His ex kisses him in class with other students around them and instead of pretending to care about his girlfriend who is in the same class, he just gets into the kiss and likes it... Then his girlfriend slaps his ex, kisses him, and he just lets that happen too and gets into it.

He is literally a nothing character. Besides wanting to kiss his ex in chapter 1, almost everything he does is because of his girlfriend or ex doing something. He literally can't say no to either of them even in the classroom situation that makes him a scumbag in public.

Won't even hold her boyfriend's hand after 6 months of dating because of a trauma she has, but immediately is willing to do anything with no reservation once he breaks up with her. She immediately shows up to get him to cheat once she finds out he's dating his childhood friend now. Them breaking up feels like some extremely weird forced drama to me as well. She didn't want to do anything with MC because of her trauma, but just told him it was because she didn't want to kiss or touch him.

Normally this would be understandable because trauma isn't easy to reveal to others... Except MC already knows about the incident. Just say it's because of that. Why just say that you didn't want to and make it seem like you don't like him or something like that?

She's scheming from chapter 1 to get MC to cheat. Once they start dating and MC cheats on her, she just gets mad at the ex and a little upset and more possessive of the MC. When she sees his ex kissing him in class she just slaps her and kisses him right after.

They both give MC the ultimatum of them or the other girl. His childhood friend sends him a video of her cousin groping and kissing her, then says she'll let her cousin have his way with her if MC doesn't cut off his ex-gf completely. MC chooses childhood friend and goes to cut off his ex, who then says "if you leave me, I'll go hook up with someone else". MC immediately loses all of his brain cells and resolve and decides to date his ex in secret and hide it from his childhood friend... This is literally the same situation that led to the ultimatum. We're stuck in a loop here.

a guy cheating on his childhood friend and girlfriend constantly. Like this man can not keep it in his pants.

How morally bankrupt the protagonist is by constantly switching between the two girls. It would be one thing if he stuck to one but he doesn't. This man is indecisive and weak.