Look. How about you read up here about Love Busters and Emotional Needs and incorporate that into your relationship?

It will improve your relationship, and it will give you something to keep busy on so you stop obsessing on whether he's going to marry you.

fwiw, if he hasn't even proposed yet, it's a pretty good bet he doesn't really want to. Maybe you could ask him about himself, instead of about the relationship. Like what he's expecting out of life, if he is where he thought he'd be, if he's missing out on anything, what he would change...stuff like that. It sounds like you may not really know what he wants or thinks, you've just been in a rut for so long that you're taking each other for granted. Work on that, and then see if you really should be together.