How fast is too fast?

I recently started dating this guy. He's super sweet and caring and I really enjoy spending time with him. It's one of those things were I feel like I've known him forever. But, last night.. Things got a little steamy and so I had to stop him because my head was screaming "Too soon! Too soon!" We talked about it of course and well me being curious I asked if he was a virgin or not. As I suspected, he wasn't. Which wasn't a big deal I mean he's an older guy but he told him that with the girl he'd been with they had waited over a year into their relationship to get to that point. I don't mean to question everything but, if he waited so long then, why does he want to go so fast with me?