Both of them would have been in and out of relationships. I think if they split up and went to different colleges, Eric would have still been annoyed by how vapid and stupid people are so his anger I think would have remained. Dylan would possibly still feel left out even if he (very likely) found himself a solid group of friends, and I could see him having a girlfriend but still not feeling fulfilled. Eric's first girlfriend would be his "life", and not in a good way IMO. He'd be very obsessive and possessive of her, and it'd end badly. One or both (probably Dylan) would use alcohol to cope. I think around maybe late 20s they might chill out and start to have more average lives, but their early-mid 20s would probably be chaotic.
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And thus I clothe my naked villainy
With odd old ends stolen out of holy writ,
And seem a saint, when most I play the devil.