My fiance died: why is marriage so important to me?

I have beaten Google half to death trying to find an article, blog entry, facebook status, tumblr account or hashtag that might give me some insight into what I'm feeling, what I've been feeling, and why I just can't stop wrestling with it.
I was married at 19, divorced at 21, engaged at 23, and lost my fiance at 24. I hastily married someone who was, and still is, a wonderful friend, but was never meant to be any more than that, and we divorced within months.
The fifth anniversary of Danger's passing was a few months ago. It is the first time I think I really allowed myself to accept that he was really gone. I was convinced it was a practical joke for days after I got the news. I was 2,000 miles away, and, even as I bought the plane ticket and got a tattoo with his nickname in it, I was certain he'd call me, laughing his deep, roaring laugh any minute.
That call never came. Some part of me still can't process it, but maybe that's what grief is.
The man I love, the one who's still among the living, was my friend. He paid for me to get obliterated drunk two days in a row and made sure I was taken care of around that anniversary. He didn't try to take advantage or cross any lines. I knew well that he had feelings for me, and I for him, but I wasn't ready. I was single over a year before I met him. He'd been my friend before he knew about Danger, and he remains my friend even now.
But now, we've been together for four months. We spend more nights together than apart, and we work as a team in every aspect of our lives outside of his work and my schooling.
I've been divorced twice, and lost the only man beside him that I've ever both loved romantically and trusted. Why, on God's green earth, does marriage feel so important to me, to my future?
This man was with a woman for ten years and never told her he loved her. He was never in love with her, but they raised two boys together. He knew he loved me within two months of us dating, and says so freely and without hesitation.
We are not considering marriage any time soon.
But it hurts me deeply that it is something he feels is unlikely for him. I can't explain why.
I don't want to change him, I am not alright with any thought or emotion that tells me otherwise, and I haven't asked him for that, nor would I ever. I make my own money, pay my own bills, and live on my own. In reality, he would stand to benefit more financially than I would should we get married.
There is no logical reason I should feel so strongly about this, why I should want this so much. And yet, I desperately need to know why I feel this way. It is tearing at my soul that I want this and don't know why. If I know why, perhaps I can change my thinking to adjust my feelings, or simply know why they exist and be able to ignore them. I do not want to ask anything of him that he does not want, I do not want to ask him to change or do anything so major for me. That's not fair, and it's not right.
I cannot find the reason. I feel lost and scared and I'm terrified to let my emotions get the best of me and end up bringing this up to him even one more time. He doesn't even get upset, or mad, or sad or anything. He's wonderful. But I hate myself for wanting this so much. He's absolutely amazing and I don't understand why I have to want more than he's already giving me.

The Art Of Death

There have been four deaths in the last three or four months of regulars from my bar- some not even in the area, but while they were out of town. Most recently was the sweetest, silliest girl I've ever known, who passed away after several days on life support.
Last Thursday, we had a very quiet, uneventful night at the bar. No fights, a small-ish crowd for a Thursday, no big thing.
And then closing time came, and I was working the parking lot with three of the guys.
To say a fight started isn't an accurate description. We heard yelling, I saw an arm raised and come down, and I pulled a young man off the fight the male bouncers were already trying to break up.
There was so much blood.
I hate it when it's soldiers fighting- I spent more than five relatively uneventful years as a US Army Medic and, truthfully, I've seen more medical trauma in the three or four months I've worked at the bar, from seizures to fights, etc.
This was the worst I've ever seen, though.
One of our bouncers caught a couple nicks from the knife.
The young man covered in blood had some very serious injuries. I just held pressure and talked to him, trying to keep him as calm as possible. There was so little I could do for him, and the injuries were so bad, I didn't think he'd make it until the ambulance arrived. He was so sweet and funny, and so young.
He lived, though, the police told me when I left the station at 6 the following morning that he was still in surgery, but doing far better than had been expected. I cried.
People at work have called me hero and told me I saved his life, and maybe- MAYBE- that's the case, but really, who's to say? He was a fighter, he wasn't giving up that easily and it just wasn't his time. I'm just glad he survived.
Today, I get a text message.
One of my favorite battle buddies took shrapnel in Afghanistan, but has been taken to Germany and is in stable condition.
I've lost a lot of people in my life- far more than most people- but the numbers on this are really starting to scare me. How many people I know will be hurt or killed before this horrible streak is over?