Definition: Given a real-life anecdote of a complex ethical situation, generate a suitable title that describes the main event/root cause of the situation. Imagine that the given text is a social media post, and you have to write the title of the post, so the users can decide to read the main text or not.
Input: A girl I dated a few years ago and I have remained good friends since our breakup. I've still had romantic feelings for her since then and the past 2 years she's been dating this guy that nobody seems to understand them as a couple. I've never cared for the guy despite my best efforts. I want to support her more than anything and if she's happy that's great.

I've known the past few months things between them have been pretty rocks with multiple times of them almost breaking up. They have an apartment together and their lease runs up this summer, so staying together for the time being makes sense on a lot of levels.

Last weekend I get a call from her at 1030pm asking if I can come over because she might need some help. 20 minutes I show up and knock on the door, she comes out with her dog on a leash and wearing a hat. She is clearly upset and after we start a walk she says that he hit her.

I ask if it was open handed or a fist (not that it matters) and she doesn't know, she just knows her cheekbone hurts. Apparently they were is a super heavy argument, which has become the norm lately, and she shoved him. His response, from his perspective, was he tried hitting her hat off her head. But then she tells me this isn't the first time he's hit her but the second time.  After about a 45 minute walk she goes back to the apartment.  

Since then I don't know much about their interactions hut I've understood she has been looking around for a new place. She's been staying in the spare bedroom and he's been in the master.

I had an opportunity to see him tonight at a social event and in private I approached him, stating if he touched her again he's gonna wind up in a hospital. He asks if she told me what happens and I say "yes she told me. Get home safely" and then walk away, to which he responds FU.

2 hours later I check my phone and have 3 missed calls from her and a text saying "wtf"

I haven't been able to talk to her since then, but AITA for stepping in? I just want to protect my friend, romantic feelings aside. How could she interpret this to make me out to be the bad guy?

sticking up for an ex