You just kind of accept that it won't necessarily be forever. Not like life has any guarantees in it either, y'know? People break up for all kinds of reasons, life is fleeting, etc.

It's about appreciating the moment before it's gone. ( and all her relationships or quasi relationships or not-at-all-relationships that happened when she got the chance to live her two decades of life were like that: fleeting. for one reason or another, death or distance or falling apart. )