My bf is addicted to his xbox?

hi iv been with my bf for a year now and at first he didn't even mention he had a xbox then we moved away and he started playing on it alot he got the new codmw2 he plays on live all the time we moved back to our hometown thinking that would help been back with friends but they all play it to, he used to be a happy nice bubbly person now hes moody he shouts alot and hes put on loads of weight he goes on when he gets up till my sons come home from school then again at 6 when i watch my soaps lol he comes of when i go to bed then the next day he starts again he goes in a mive huff and kicks of if i ask him to have a few days of it feels like im his mam hes 22 years old and we have a baby due in 7 weeks my sons are 6 and 8 and my oldest son loves games as well but i don't want him to turn out like this so im putting my foot down with him just wish i could do the same with my bf i just don't no what to do we have fell out so many times over his xbox iv lost count and i don't need the stress right now i just want the man i first met and fell in love with