Complex sentence: She then publicly breaks up with him, unintentionally insulting him with her brutal honesty (telling him that she no longer finds him attractive, and that she "Cringes when (he) talks"), leaving him humiliated and hurt.
Split into simpler sentences: She then publicly breaks up with him and unintentionally insults him with her brutal honesty. She says that she no longer finds him attractive and "cringes when (he) talks", leaving him humiliated and hurt.