The answer is hiding in plain sight. You beat him to often.
He likes video games, but isn't very good at them so he plays single player games where he can lose, but not be beaten. I do that a lot myself. Bad enough to lose, but to be beaten by the other player all the time is worse.
I don't suggest that you lose on purpose. But you might try to find a game that you are not especially good at that he might be interested in playing.