Stealth marriage is pretty common. Women's groups and divorce lawyers make a natural coalition to lobby for various gotcha(s)
I am sure I can get along fine with a love relationship near at hand but me living alone. I think you get a little more sex if you are in a committed relationship and live together, compared to the same relationship with separate beds. Still, to me it is not worth the added risk. If I found out that I got accidentally married I would be one unhappy man. Also, certain events that might claim your life if alone might be handled better with a live -in partner, but again, once you are dead, not much difference.
Ha