<human>: Dating for over three years now. We recently took the plunge and moved in together, and it is not working out as great as I had hoped. I guess, living apart, I didn't really get to see how often he played video games. Really, that's not even the problem - I don't even care if he plays video games all day right now, we're young, and he gets everything else he needs to done. I just do not like the person he becomes while playing video games. He becomes infuriated when he loses or someone takes a cheap shot in a game - and apparently every shot is a cheap shot, and something is always not fair, because he is *constantly* complaining and shouting and bitching and moaning. The entire time he plays. 

Tonight, he got so mad he slammed his computer shut and stormed off to bed without even so much as a goodnight. And honestly, I don't know how much more of this I can take. I am actually less sexually attracted to him because of this behavior. I had no idea that he was like this with his video games before moving in - I didn't know I essentially signed up to live with a man-child. 

I have tried to talk to him before about how much it bothers me when he shouts and complains for hours on end about the game - he hates being called out on it. He says he knows he is a bad sport, he always has been. He also claims that he is trying to change, but I am not really seeing it. All that conversation does is make him mopey and not really accomplish anything. 

Predating this, our relationship was great, and this is really the only major problem in our relationship, so I don't want to break up with him - but I am seriously at a loss as to what to do. Break the game? I really don't know.

Can you summarize the given text in a few sentences?
<bot>: my boyfriend massively overreacts when playing video games, and he plays a *lot* of video games. I can't handle the constant complaining and shouting through the house anymore.