Question for guys?

my ex and I haven't dated in over a year..well he asked me to move in with him a few months after we broke up, but I decided against it because I was unemployed at the time...recently I was dating "craig". After craig an I broke up, he asked me to move in with him as a roomie, making this the 4th time he's asked me to stay..but since then we've been doing a "friends with benefits" thing, and he still bring it up...what's the deal? He says he doesn't feel a "spark" but gets jealous wen I mention other men..and still brings up me staying with him even tho he said he's a "commit phobe" ...explain this to me!! Make a man manual!! Lol