Simon Castellan.
He's possibly one of my favorite characters and definitely the most entertaining one I've created, but oh my god he can be really terrible.
Horrible boyfriend: He's so demanding and emotionally taxing to be around. I don't even know why girls (or guys) put up with him. Simon is always complaining and usually criticizing his romantic partners. Simon also has the tendency of getting close to people only to break it off once he gets bored or things get more difficult for him.
Micromanaging others: Simon's worst flaw yet also the most fun thing about him as a character. Simon is by no means a villain, but the means that he uses to achieve his goals are a bit questionable. He manipulates others and plays with them like chess pieces, because he's convinced that only he can get things right.
A bit ruthless: Simon is not afraid to take hostages, assassinate or use political/emotional warfare. He aims to kill. His actions are for the benefit of his group, the heroes, but Simon really has moments where you are not sure if he's completely on your side or not.
Sarcastic dick: He always has some sort of joke or remark to make about someone's situation. Simon loves to pick out people's insecurities. But god forbid someone does the same to him.
Emotional Theatrics: Simon has some serious mood swings. Simon seemingly flip flops demeanors at random. He's either a nice, cool guy or a huge dickhead. Plus he has horrible taste in romantic partners. He's practically drawn to women (or men) who are dangerous and unstable.
So yeah, I'd slap him, tell him to stop whining and to be a better person