No matter how and how long you've been together, she's never been satisfied with you and she's been looking over you for someone else of certain type, which probably she herself is uncertain about. Lucky you haven't been heart-broken due to some more faint , uglier scenarios; Poor guy, you're just NOT THE ONE for her.
Agree that every normal human-being needs companion unless s/he is out of mind. Sounds awkward to be related to career success. Who'd care as long as there was the feel!
Man, be realistic a "byte" and look ahead for your fortune which apparently doesn't lie in that girl at this moment of your life, or forever.