Don and Megan

When Megan breaks up with Don, he offers to give her everything she needs because he "owes her that much". She says that he doesn't owe her anything, and she seems to mean it.

A few episodes later, she's all about how Don "ruined her life". Come again? How has her failings as an actress been Don's fault? Yes, she quit her soap for him, but here's the thing:

-She *wanted* to go to California. She was damn well eager.
-She had, in fact, dreamt of California for some time, but stuck with her soap because Don lived in New York.
-Don's suggestion that they move to California, then, gave her just the opportunities she had always wanted.
-Don decided to stay in New York. But so what? Megan moved to California anyway. Would her career be more successful if Don had moved with her?
-When Don suspects he is getting fired, he suggests he could move in with her and start over in California. That's when she breaks up with him.

In short, Don gave Megan a chance to pursue her ambitions. He is not to blame that she failed to land the big parts.