Why would a guy flirt intensely, show affection, act like your boyfriend and not ask you out?

I've been spending the past 5 weeks studying with a male friend. He tells me I'm beautiful, talented, a real fox. We both boldly flirt with each other. He stares at me often, looks into my eyes and is very affectionate with hugs, hand holding plus a little slap and tickle here and there (aka: lot's of touching). Also, if I call he's very attentive and extends the simple conversation well past the regular point necessary for a call about essentially nothing.We're on a break now from cl and he hasn't asked me out and he hasn't tried to take this heavy flirtation any further. I've casually asked him on two occions and the first time he couldn't make it because of work committments and the second time he needed to take his car in for repairs. He apologized and seemed eager to reschedule but so far nothing. Though I've felt a strong physical vibe from him at times, am I simply confusing a really "nice" guy with someone who has real interest beyond friendship or what?