In my life experiences a good marriage is a good marriage, RVing works because the marriage is good and both enjoy much of the same life style. A bad marriage is a bad marriage. Things don't work because one person wants to go this and the other wants to go that way. There's lots of bad marriages that will remain bad marriages because they're both too stubborn to fix things.
Rving couples that both seem to enjoy Rving is an indicator that the negative things have been worked out. I believe it more so for couples RVing in a small trailer.
Long marriages are NOT necessarily a sign of a good marriage. We were camped next to a couple this winter that had been married for a number of years and fought from the time they woke up until they went to bed almost every day. No day went by with a fight. Across from us were a couple that had also been married for quite a few years and they seemed to be doing just fine. Both couples full timing.
I consider my self very lucky. After a failed marriage, I found a lady or maybe she found me, that I consider my very best friend. We've been together for just over 30 years and manage to be together 24/7. Living in our 13' Scamp
is a real joy and tons of fun. We manage to give each other enough space so that nobody feels smothered, and still enjoy doing lots of stuff together. We even share many of the same hobbies.