My attitude toward relationships has been a combination of self-sabotage, yet at the same time being clingy. I think it has made me a very confused person at times.

But basically for me knowing whether it was really over or just a rough spot was based on whether the problem we were going through was something that I considered tolerable. If it was a tough time but clear that we could work out these differences and we both wanted to, then I would not throw in the towel. However, if it was something where the other person's behavior was not acceptable and I had strong doubts that real change would occur, I would realize it's time to move on, no matter how hard that realization may be.