Well: Most relationships involving romance have phases. Infatuation, what old novels used to call "smitten," doesn't last more than 18 months, if I'm remembering what I've read correctly. There's research on this somewhere, you might want to probe that aspect of it - the phases of a love relationship - to, oh, I don't know? normalize your expectations? Get a reality check 18 months before you need it? There are various points in a relationship where either person can make a decision; sometimes you get unfortunate situations where one party is done but still harbors enough affection for the other that he/she just endures rather than cause pain by terminating. Much to think about, but you're probably going into this better equipped than many.
Generally, the less time invested before a breakup, the easier the breakup on everyone. Tough in the first phase no matter what, because emotions tend to be high along with expectations.
I wish I'd known all this when I was young.
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Life would have been very different.