The dreaded C-word; cheating?

So I've been doing some research on the web about women and why they cheat, and what to do after they've cheated and confessed, and blah blah blah... I've felt unhappy with my boyfriend, but I really don't know why. The sex doesn't feel passionate, just rough, I feel like the person I fell in love with is only there sometimes... And I've brought these concerns up to him, all he does is say "I'm sorry, I'll change it", which the thing is, I don't want to change/control him and I wanted him to fight back, to deny it, to put some thought into it... Maybe that's my problem, that I don't feel like he's all here. He's told me that he hasn't felt like himself since he started working, and he has a stressful job that is going to compound when he gets career job... Maybe this is something that will never change, but I had wanted to by the amazing supportive girlfriend of a cop...

These are all thoughts I've had for the past 6 months, but it was compounded by a guy tonight; I'm a firm believer in never playing the "what if" game, so I went for it. Turns out he is completely attracted to me, we have some similar views, some very different views... I'm more cynical, he's more sweet, but I'm really attracted to him in some ways... But I don't know if I could see the long-term with him...

It basically comes down to a guy I really hope I could make things work long-term, versus a guy I would want to try having a relationship with (we've flitted in and out of each other's lives over the past 5 years). Obviously I'm going to get a bunch of random answers, and this other guy was so sweet, he told me to really think about it and to give him a decision. He is really kind like that, and he's the type of guy who's always thinking about others and letting himself get kicked in the mean time. I've told him throughout the times that he has to start standing up for what he wants and what he needs from life... I feel like I've walked my current boyfriend through most obstacles (but now he's a very different person I've molded, which I kind of hate), and if I were to be with this 'new' guy, I'd end up trying to help him grow as well. I don't know what's wrong with me *sigh*.