Are there stories of successful long term V's where two are respectful and loving but from a distance? I am guessing it depends on if your desired outcome is to create family.
I think it does depend on one's desired outcome.
FWIW, I was in a very happy V for 2 years. My guy was married w/ kids. I knew his wife socially and to say "hi" to and we were friendly and respectful of each other, but I had no desire to become a full time part of his family and she was happy enough for him to have a g/f, but didn't want him to bring in a "second wife" as it were. Basically he had his home life (primary) and he had me (secondary).
I was very happy in that situation and would have been happy for it to continue indefinitely, but ... things happened. We wound up splitting up mostly due to his wife's jealousy and control issues after he was diagnosed with a serious illness.
I would say that if the illness hadn't happened and brought up a lot of issues that most couples don't have to deal with, we would have remained in that relationship for a very long time. Unfortunately it wasn't to be.