But generally speaking, boys will do this. Many times, the purpose is simple. After all, playing games won't be a big problem. Because in the game, it is not easy to meet girls. Several people get to know each other and become friends, or play games together. More often, just to find a partner for yourself. Not as many girls think, the boyfriend has changed his mind.
Of course, there is also a situation where boys themselves like this ambiguous relationship with many people. So they will meet more girls in the game and often play together. This situation will show that the boy has no deep feelings for his girlfriend, or has begun to dislike his girlfriend gradually. If that's the case, it's better to get to know each other and separate.
So I think since you don't like your boyfriend doing this, you can tell him directly and ask him why, so that you can know if you really don't like yourself and then decide your future behavior.