How do you know when you're meant to be with someone? Like, forever? Of course, this is a difficult question to answer. On the other hand, there's another way to look at it: How do you know when you're not meant to be with someone? What's more, how do you know when your relationship isn't built to last-- like, at all? Over on Reddit, men and women recently opened up about the matter and... Well, here's what they had to say.