In general, I'd agree that it is damaging, but it depends on the person.
Some people have the capacity to lift the books, but others nearly suffocate themselves.
It's hard to say what's 'fast' or 'slow' as each person holds different 'norms' or 'standards'.
I know some who've dated for years, and then been happily married.
I know others who dated (as in...weren't even friends really) for 6 months, and then gotten happily and lastingly married.
Though generals apply in general, almost everything largely depends on the specifics (people, time, society, situation, nature, ext...).