You've got to have a relationship with yourself and confidence in yourself to know when enough is enough. If you don't value yourself, who will? truth is nobody will get everything they want, it just doesn't happen, fairy tales don't exist, compromising does. You get enough to keep you happy, the scale should be unbalanced when it comes on to you being happy as opposed to being sad in your relationship. You have got to evaluate your life, ask yourself are you happy? are you satisfied? are there things in my life that could be better? communication and being open and honest with your partner does alot for a relationship. When you enter in a relationship you leave the i, me and mine at the door, everything becomes us, we and ours, some people fail to do this, causing alot of problems in their relationships. They get caught up in self serving things, that affects their relationship in a negative way.
Nobody likes to be treated like they don't matter, or like they aren't important. Alot of things can make a relationship feel like a burden. Being controlling, name- calling, getting mad for everything without having a reason, making the same mistakes over and over again. You have got to ask yourself if your relationship is good or bad. Many times bad relationship can make you feel bitter, or you start to develop a I'm going to show you how it feels attitude and then your relationship get's even worse. Then you end up not wanting to be around your partner. I think when a person has had enough, what else is there to stay for, you'll start asking yourself, how is being in this relationship benefiting me, I'm being beat down every day, I'm sad everyday, then ultimately their going to leave, there is so much that a human can take, we have a heart and feelings, we know when something is write for us, and when something is wrong, some people just choose to ignore those feelings, follow them, they usually aren't wrong.