I kind of know what you mean, it’s like telling a depressed person to think happy thoughts. If it was that easy we wouldn’t feel so bad. ‘It wasn’t meant to be’ it’s just an easy thing to shrug and say, and while it may be true, doesn’t really help.

As to why the relationship ever happened, life is a journey, not all experiences are meant to last forever. The breakup hurts, and you might be recalling only the bad times after a bad breakup, but it wasn’t all bad, and you learned from it. It happened because it’s what you wanted at that moment. It might not be a ‘forever love’ but it was perfect for that moment. Maybe these two people will get back together one day, maybe not, but one day you might look back on that time and smile because of the memory or lesson.