I can't give you an answer there.
I've stayed in many of those relationships and been unhappy, but I was drinking then and I was a whole different kettle of messed up fish lol
I'm not sure what my response would be now - I like to think I'd be strong enough to hold out for the kind of relationship I want, but a companion style relationship certainly seems to be going ok for people I know - I think it gets more attractive the older you get too
D