Haruka is right to be upset with her ex' actions. Ultimately, her ex decided for her what she should do and broke up with Haruka giving a lie as her reason to force Haruka to make that choice. The given reason in particular being a part that Haruka's struggling with. Having even her girlfriend use this against her, it's all very cruel.
Ultimately she should've just told her that she thinks Haruka is making the wrong choice and why she thinks that. If Haruka still wants to stay then that's her choice (The choice is hers! Partial title drop!) and ex should not feel responsible anymore. Instead, view your partner as a human being that can make their own choices, like an equal.