Hi. Really interesting topic, something I've been thinking about for a long time now.
I've been married twice. The first time, I had an affair very shortly after we were married. We'd been together for about 4 years, got married, and within 4 months I'd fallen head long into an affair with a work colleague. I could have saved the first marriage, but I chose not to. I didn't trust myself: I felt once I'd been unfaithful (and I mean not just physically: I had fallen in love with someone else) to my first husband, I couldn't guarantee I'd not do it again. I was 23 and young and really felt it was necessary for me to let him go and be free.
I'm currently very happily married to my husband of 9 years. It's been a tough 9 years. The toughest parts, however, are just normal "living" type things e.g. money, health issues, work issues and so on. Are they unique to a marriage? In my humble opinion, NO. Did being married make me any more determined to work through those tough times? No. What did? I simply really like the guy

I care for him a lot. I love him as a person, as a human being, as my best friend. Romanticism aside, we're great mates and I'd do anything for my great mate.
I'll be frank and say I have no idea why people get married

I could easily just live with my husband as a good friend and I'd be just as happy, I think! If people think that "getting married" suddenly changes them, their status, becomes a life-long romance then this is a romantic ideal and not realistic.
Why did I get married again? Because I felt I wanted to! I really wanted to. On reflection, I'd not marry again. I see it as an unnecessary societal convention nowadays, and a blimmin expensive one to boot!
So in terms of a marriage's worth: depends on how you view marriage, is it something you feel you must do, are their religious norms you observe that require you to be married? I'd think more in terms of quality relationship. If nothing else, I believe I have a very high quality relationship with my husband. We communicate really well, we look after each other really well, we respect each other a lot and want the best for each other. That to me can be done regardless of a marriage.
Hope these thoughts help
Cheers,
Jenny.