Marriage makes it harder to walk away when times get tough. After all you are in a legally bound contract with one another. I for one love being married. We met as witnesses and now I am no longer one. However, my husband thinks he is but he really isn't. He's one of thoses i only go every now and then (once a yr.) guys. Either witness or no witness, I think marriage is a good thing. We've had our problems but I'm so glad we've decided to work on them instead of walking away from them and each other. We have been married 10 yrs. now and I hope we are married forever.
Now that's just us. I don't think mariage is for everyone. For some people I do see them more unhappy after they've made that commitment. I think what might help is for a couple to live together first to see if it'll even work out. And, always to remember to really value your mate. I think over time a lot of couples just start to take eachother for granted, and in time the love they once had just slowly slips away.
So, I guess my answer is... it all depends on the person and what the want. Just my opinion.