Compromise is the key here.
I do believe that the not wanting to compromise is a side effect of a shift to materialism and egoism - moving away from a sense of duty, sacrifice, community etc.
We subtly (and not so subtly) conditioned to expect instant gratification and to move on if we don't get it. This is not just in physical relationships, but in comfort, jobs, entertainment etc. Escapism in front of a TV or internet or in drugs and alchohol are inextricably linked to this false expectation hitting against reality - I think.
Thinking it is ok to be s.exual before marriage is one thing (and indeed, a good argument can be made for experience, etc) - but I see this as just another symptom of the commercialisation/commoditisation of what in reality should be a part of a long-term, loving relationship where the primary aim should be companionship and raising of children, IMO - not the passion in the bedroom.
Anyway, my point is that let's get beyond the marriage certificate issue when looking at this issue - but rather go to what I think is the root - how we view s.ex and that it is increasingly becoming separate from long term relationships. There is even a polite term for it now - 'friends with benefits'!
Cheers,
Shafique