I really think it depends on the age and experience you have before you start taking relationships seriously. It's most definite that when you enter a relationship passed the age of 25, you think that this person may potentially be your future husband/wife.

But for a high school crush, you don't think along that tangency. Even when high school relationships do work out and they end up marrying, it's not like they had entered the relationship and expected to get married. The biggest concern of h/s couples is just making it through.

Some people enter relationships on a moderate level of attraction. It really depends on the person. >>40 sounds like an idealist and a strong sense of moral. So he will truly value his relationships. Even so I think that if he were to start dating a girl, he cannot automatically think 'she is the one'. It's only till they have dated for a while and their attraction is reasonably strong, do they start thinking along these lines.

So there's always a 'dating' period before couples start taking their relationship seriously. You can call this the stage where you gain experience. It is like practicing but using the word 'practice' is just offensive to the romantics.