Why won't he marry me?

We've been together for 4 yrs, 2 kids, good and hard times. When he refers to me he says "his wife", but when it comes to making it legal, he has an excuse everytime "not enough money, bad timing, too many other things going on, ..." I'm to the point I don't care if we go to the courthouse, at least we will legally be married. Now his excuse is lets wait and make it 5 years. I'm sitting here like you want me to go ANOTHER year with people constantly barrading me with "when are you getting married". He doesn't get it like I do, his friends don't care, but EVERYONE from family, co-workers, friends asks me ALL THE TIME. I'm so tired of saying I dont know. But my competitive side has kind of put it on a time crunch. There is this couple I know who are always a few months behind us on milestones (getting together, kids, living togeth., etc...) and they just told me they are getting married march 7th. So I'm like ok if they are getting married we should already be planning. So what gives?