Zurge, and any other people out there like you, what's the problem?! No offence, but seriously do you know how lucky you are with this guy?
Ok, for a start; 1) Text conversations rarely go on for more than five minutes with a guy let alone five hours. Obviously he really likes you or this wouldn't have happened more than a couple of times.
2) The way you described him holding you from behind is not very common. Not many males would feel so comfortable in that kind of position/intimicy, let alone with other people around who can see. And he initiated it, which is bold of anyone.
3) You said he didn't seem to care when you rested your head on his shoulder or whatever. This is a great thing so definitely try touching him further and see his response.
4) How about the break up? Perhaps he wants to pursue other interests now...
I live in a particularly homophobic society and have never had the chances you do. So I am strongly aggravated by your discression and reservation.
Even if he isn't bi he could be a great friend (presuming you're not already). If he's as sensitive (or at least communicative) as you suggest, at some point (depending on how long you take to get it together with him) you should be able to talk more deeply about whatever it is you want with him. It could be he's just going through a phase where he fancies the pants off you (not neccessarily literarly) and you don't have to admit that you're bi.
Whatever the case is, my point is this; do something. Don't waste the opportunity that others like me don't have.