Partners Unholy Smell!!!?

My boyfriend just moved in with me and he smells so terrible!! Hes constantly farting and it smells worse than ANYTHING ive ever smelt before (and we have two children in nappies!) I always knew he sometimes farted alot but living with him is getting unbearable. He doesn't eat badly and he doesn't drink alot im starting to think theres something wrong with him, does anyone have any ideas?