Everyone needs to pay attention to this scene (and the subsequent scene of her in the precinct dumping out coffe). She’s not angry. She won’t even yell at him. His words hit home because she realizes she wasn’t honest. She did hold it back. And while she thinks she did it for all the right reasons, because she wasn’t sure about where they were heading, in the end, he’s more right. She should have been honest from the get go and it pains her that she hurt him again.