She exited a long relationship not too long ago. While they were together, they definitely partied, but he preferred a more chill vibe while she was getting too into the pills. Which is why he claims they ended it. Turns out, around the time of her split, she went to rehab for a tune-up and is now sober and re-focusing on her work. Her work, recently, was rather high profile, a prestige assignment. But she was miserable in that environment, not only trying to avoid bad habits but, apparently, not getting along with her colleagues; supposedly they never wanted to hear her opinions.
Now that she’s clean, her perspective has changed too. So she’s going around telling people that the reason she’s not with him anymore is because he’s not stimulating enough intellectually even though she was so attracted to him. There were a lot of romantic gestures, like dedicating his art to her, but ultimately she’s revised their history to read that she left because she wants someone smarter.