Advice I heard once that I agree with: "People who lie to you, habitually, aren't doing it to protect themselves. They're narcissists. They think they're better than you. In their minds, you are inferior to them, so the idea of enhancing their image to be more appealing to you is laughable. They do it to control you. You are an object they master through dishonesty."

It's true.

There is no equity in the type of relationship you're describing. A person who lies that much doesn't respect you. The cheating was simply a manifestation of that disrespect.

The concept of breaking-up is probably absurd to her unless you become inconvenient or something. I'm not saying that to be a hard *** either. People are a mixed bag of emotions. For all the positive emotions you think she has for you, you have to at least concede that she probably has a lot of negative emotions for you as well. And people can be extremely cruel when they rationalize their own behavior using those negative emotions. She's likely done that.

When you become AS objectified in a relationship as she's done to you, you have to end it because now she's just waiting for you to become boring enough or inconvenient enough to justify leaving you. And I honestly believe that is her end game. You don't stay in a relationship with someone you do not respect.