Boyfriend w/ no sex drive

Miranda
Been with my live in boyfriend for over 2 years. He's never really been crazy about having sex. Not that us making love isnt hot and meaningful. But as time has went on it seem to be a chore to him. Makes me question myself; insecure, basically. Becomes a fight. I cry, trying to get thru to him. Wondering If I'm the problem. Question our relationship daily. The list can go one. But he just keeps saying it's not that he doesn't want to, just cant. Like 'WHAT THE HECK DO YOU MEAN, DUDE?!?' I guess is anyone else in a situation like this? Or is he not human? Gay? Trust me I've considered all options..