Here is the thing. It's not that your guy doesn't love you, it's just that you have given him every reason NOT to get married. A guy's mentality is "if it ain't broke, don't fix it." A girl's mentality is to live out romantic dreams no matter what.."I've dreamed of a gorgeous wedding since I was 5."
Reassess your relationship. Have you guys ended up in a relationship that already feels like a marriage? Are you doing the dishes, living together, sharing expenses?
Perhaps, there are certain things about you or your life that the guy is afraid committing to legally. Is your dad a nazi? Are your religions different? His thinking is, if he doesn't tie the knot, he has more wiggle room to escape these things without legal docs binding him to them. So even though he loves you, if things go sour in the relationship, he can always escape them!
What you need to do is something different. Stop bugging him about marriage and insinuate the idea in his head, make him think it's his idea. Right now, he is afraid to marry BECAUSE HE STILL FEELS SOMETHING IS OUT THERE THAT MIGHT BE BETTER. Which means he is uncertain of the future.
-Don't rush anything
-Insinuate the idea of marriage in his head
-Do things without him, like join a fitness club, get out there...find hobbies. WHEN YOU ARE BUSY and making friends, he will start missing you, realizing how awesome you are when you are out and about in the world instead of always being around him.
-Let him know that you already love him for everything that's going on and don't baby him or try to change his behavior or anything. Don't play any covert mind games, like telling him about all the men interested in you...TURN OFF.
-Get rid of "marriage-like" settings in the relationship and add back some spontaneity to the relationship you had before, add some spice...take some tantra yoga classes, sign him up for some dancing lessons, watch a dirty movie, these are just examples.
-Take a look at your relationship and find out all the consequences that marriage can have on you guys now.