I’ve had to field this sort of thing a lot, and my response is pretty much the same. I’ll never regret the good times I shared with someone even if a relationship ends before I wanted to. Yes, I always mourn the end of a relationship, but in the same way I mourn the death of a friend. When a friend dies, I don’t bellyache about how I wish I’d never spent all those years putting time and energy into cultivating that friendship. I cherish the memories we created together, however sad it might make me that we won’t be making more. I don’t see why the end of a romantic relationship should be any different. Time wasted being bitter is time that could be being used to form new connections. I want to always more towards where more love is, not stay stuck in an empty space where love used to be.