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: Tl;dr: GF went out with her friends. She then sent me videos of her dancing with two guys at someone's house. I got angry. 

Sorry if I get a bit incomprehensible, I've got quite a lot of drinks in my system. I'll give you a bit of backstory:

I've been with my girlfriend for a half a year. We knew each other for a few years but we started dating just recently. I've moved into her city for a university and we really hit it off. We've got a lot of in common, we like the same movies, we like to take walks, we have similar sense of humor etc 

The issue of cheating never really crossed my mind since everything was great. Her family likes me, my family likes her and I'm even planning to help her brother build a PC as a kind of bonding experience.

I never wanted to isolate her from her friends, so whenever she wanted to go out with them (a mix of male and female friends) I had no issue. But this Friday seemed a bit off.

I've been out of town due to some family thing and she went out to a bar with her friends again. I've been working well into the night so I expected some texts or photos from her, as was the usual. She sent some things but around midnight she sent me goodnight message. I asked her if she was at home, she said no and that she didn't want to text afterwards. I've been okay with that, she's been drinking after all.

At around 2 am she sent me two videos on Snapchat. In them, she was singing and dancing with two of her male friends at someone's house. I didn't see anyone else in the videos, so I assumed they were alone in there. She sent me a message at 5 am that she was finally home and going to sleep.

When I saw that in the morning, I got really angry. I didn't tell her though, even though I probably should. She even asked me if I'm angry and I said no but I'm pretty sure she can tell that I'm not ok since I haven't been texting her at all.

Am I wrong to get angry in this situation?

getting angry at my girlfriend