You have got to talk to him about it. If he really cares about you he'll be open and responsive to what you're feeling.
Sexual frustration can ruin a relationship if the couple doesn't talk out their problems and actually understand and work on what each other wants. If you need more variety, a sex toy, more foreplay, more spice, you have to let him know! If he hasn't figured it out on his own in all this time, he's never going to!
If you don't want to flat out talk about it, suggest something that interests you.
If you think...for example, that a sensual massage will get you more interested, go buy a book about it and get him to read it.
If you want to receive more oral sex, try buying a flavored lubricant made specially for oral sex, and showing it to him. Suggest using it on each other (though you might want to make sure he uses it on you first, just to make sure he doesn't change his mind after he finishes first).
If you think he's not paying attention to your sexual needs enough, mention that you felt turned on by something or other and wish he'd try it more often, or something like that.
You get the idea, right? You need some kind of communication to break down the barriers between what you want and what he thinks you want.
If he isn't responsive, or just doesn't care, then you know you have a bigger problem on your hands.
Good luck :)
<3
Sin