<human>: Hey guys,

My[18] girlfriend [18] have already been together for about a year. She's a really open person, and i'm quite shy and silent. She's really awesome, but there's always one thing that bugs me about her. The thing is that she's too open with everything. For example, she'd talk about sex and the like with other guys, and even play truth or dare (which includes very... sexual stuff, but not cheating on me) with them without me around, or even asking me. 

I've already communicated this with her multiple times, but after a couple of days, she goes back to her normal self, and goes about this again. Everytime after this happens I always feel hurt, and I start to get depressed (I had depression when I was around 16-17, and it's recurring)

The reason I haven't posted here earlier is because I always thought I was in the wrong. I still think I do, but this has happened so many times i'm starting to wonder why this is, and I need an outsider's perspective. Another thing that got me to ask here is when we were hanging out today, and a couple of friends joined us. I left to get something, but when I come back, I find out they're watching The Girl Next Door (I think that's what it's called, not sure, but it has a lot nudity). I was fine with it, because I know we all watch movies and such. However, when we were watching, she started to put her arm around her other guy friend, who's also my friend. I didn't know at first, but later I saw it. Later on, she was kinda holding his hand in an awkward way, and she justified this with her being cold. Today's temperature was 28 degrees celsius. Anyways, I had to go then... and I just left without even saying goodbye.

I just want to know if I'm in the wrong here and just being a jerk, and if it is me who's being overly jealous of her hanging out like that. Any and all comments will be appreciated.

Condense the text into a few key points
<bot>: My girlfriend keeps on doing things with other guys and to other guys that I feel aren't really appropriate. Communicated this many times, but it keeps happening Am I in the wrong and being a jerk?