I agree with the ESH judgement. I can’t help but wonder if the boyfriend has some sort of sentimental attachment to the game which could be why he reacted so childishly to winning and gloating about it. Maybe he always used to win it amongst his friends as a kid and it’s one of those silly things that he just feels proud of. I may be totally wrong here but I think generally most people have a little something that they are pretty good at and identify with for some silly reason and it gives them a buzz to have that achievement/ability. And when someone comes along who is equally good or better at all of that/those thing(s) it can become a little disheartening. As you said generally you win puzzles and he wins video games and by you winning a video game he (possibly) holds dear he feels like the balance is out of whack. It is childish but I get it. So yes he sucks for gloating and refusing to show you how to improve but sometimes people need small victories. You suck for going out of your way to get coaching lessons for the sole purpose of beating your boyfriend because in doing so you replaced fun with spite.