I think it's pretty obvious, no one's skipping over anything. First of all, the story isn't completed, we could always find out more stuff. Like about his mom. We don't know much about her, but I wouldn't be surprised if it's revealed she is the one who contacted him after he became rich and famous. It's typical, almost a trope. Secondly, he had a rough, violent upbringing. So much so that it transferred into everything on his life: the type of work he has, the way he treats his colleagues, the way he treats his lovers, how he carries himself. It's everywhere. How could he be tender to someone if no one was ever tender to him? He doesn't know how to because he doesn't know what tenderness is. He only just recently started doing some tender gestures, like kissing Dan and blushing while at it, etc. he is doing them on impulse, he doesn't understand it, just feels like doing them. He doesn't know how to give because life taught him to just take. He wanted to be good to his mom, but she rejected him because he wasn't that important to her. Think about it: the mom rejects him because she doesn't care about him (so he's not good enough), the dad beats him and calls him a looser, the last thing he ever said to him is that he'll always be a looser (so he's not good enough). I'm maybe a little ahead of myself here, but psychologically speaking, he probably believes everyone will reject him at some point, because deep inside he believes he is not good enough to have it otherwise. So why treat people good when they'll only turn their backs on him and hurt him in the end?
So the jinx isn’t even anything extraordinary…so we are just going to skip over the part of how he became this deranged and dehumanizing towards people he has sex with???