>>719978820
Cope by realising that around age 20, even if you two had been together since childhood, she has been programmed to go out and "find herself".
And that may even be fair, if you met and bonded I finally over a mutual love of a music genre. When you get to that age, you're starting to become other people, who might not be compatible.
When women get to 20, they start to want the kind of lifestyle that can only be provided by the resources of an established man. They don't have time for you to figure things out and build a life, they'd rather run off with a 27 year old who is further ahead.
When you get to your late 20s they start to come back, again, but good luck finding somebody your own age between 20 and 30.
When you're in your mid 30s, every single woman you know will be throwing themselves at you, btw, and that would be cool if there was any biological viability left in them, but there isn't. So every interaction you have is flattering, titillating, but ultimately has no deeper meaning, and your brain and heart know it.
So there is your cope. There will be a small single-digit percentage of women who stay true to you as you approach 20, but you can't count on it. Teenage love is beautiful, but it's not forever, and you won't be able to forget, no matter how long it's been.