Has he expressed any kind of fetishes, does he seem to be a dominant type?. Me and my love, when we first started to know each other (been together a year and a half now) didn't really talk about that kind of thing until we both decided to talk openly about what turns each other on and such to better each other, turned out that she had been into bdsm and was submissive before she met me, and I was/am straight, down the middle switch.
Maybe you should do something like that if you haven't already or figure out something light you could do which you might feel would entice him, maybe pick up a cheap collar and/or cuffs, walk into the bedroom some time with them on and see how he reacts to it?. Either way, I also agree with Beagle, need to ease it in gently, don't go in full, bringing out everything and anything which you'd want him to use.
don't worry about it too much, you'll be fine. =)
Edit: A good place to find something would be
www.extremerestraints.com unless you have your fav adult shop in mind. =)