Need Advice - Gamer Couple

Long story short my boyfriend just isn’t fun to blame games with anymore. He constantly blames me and even his friends for simply not being good enough at games. None of us want to play with him but if we don’t he feels ignored get super depressed and just sleeps. An example is a game called league of legends. One night we did great at it and all was well, the next night we had a rough game and he immediately blamed my character, then the character we were fighting and then said he never wanted to play the game again. I wish I could tell him that he is overreacting and just being a baby. I wish I could tell him that none of us want to game with him because he sucks all the fun out of it. But if I do that it’ll only make him shut down. He’ll stop gaming, he won’t talk to friends, and he’ll just sleep. He has a therapist, he takes his daily medication...and yet I still can’t talk to him about this. It’s so frustrating.