I'm against the concept of "Legal Marriage" because of it's history and what it represents. Way back when, the process of legally marrying someone was put in place only to prevent inter-ethnic and inter-religious breeding. Blacks couldn't marry whites, Catholics couldn't marry Jews, etc... The concept is intolerant, out dated and just plain ignorant.
Then there's the "property" angle, whereby a woman became property of her husband under a legal marriage. That's one reason why I would never give a woman I had a connection with a ring, even one I made. The ring symbolized ownership.
In my instance, I'm legally unmarried, spiritually on trial separation. An ex gf and I had a DIY spiritual marriage a few years ago. We're still together in some ways, but we see other people, getting back together every now and then for emotional/sexual comfort. We recently discussed going the legal route, so she could get better health care coverage and I could get tax incentives, but we agreed it would ruin what we have.
To that end, I'm still fairly young, and I doubt I'll ever be legally married. I don't need to prove anything to anyone.