I've been reading and reading this thread since it was first posted and deleted several responses, but here it goes again.
I'm a widow. I'm 36 years old and my husband died of a heart attack, in my arms, in front of our children when he was 31 years old. He died 2 months before our 10th anniversary.
Marriage meant everything to us. It meant that when he got sick, he knew that I would be there for him. It meant that when I was given a very unhealthy prognosis after our daughter was born, he was there for me. It meant bills, houses, taxes, in-laws and several other mundane facts of life. But it also meant laughter, love, 2am cuddles and middle of the night love. Any and all of this could have been with or without the legal vows.
But the real kicker is that those 2 months cheated me of any survivor benefits. I am working my a$$ off now with a part time job, full time college and raising our children so that I can give them a decent life. If he had held on for an additional two months, I wouldn't have to worry about how to pay for groceries or rent each month because the government would allow me to access his social security. Instead I'm working myself to the bone to try to finish school while working while dealing with children who have had their whole lives ripped from them.
So, to me, marriage is more than just the love, the security, the being with your best friend. It's also the difference between being acknowledged and having years of your life figuratively thrown away.