<human>: So I've been in love with this girl for 8 odd months and a little over a month ago she finally started to return my feelings. We're now in a relationship but I found out that while she was at a party she and her 2 best friends [also girls] had a 3-way lesbian kiss. The thing is that their friendship has always involved making out with each other. I haven't brought it up with her because I don't want to be possessive or controlling and I don't want to make her change her relationship with her best friends but I just can't stop thinking about it. All of my friends say it's awesome and that it's not cheating but it gets under my skin. Plus, the fact that she didn't tell me about it and I found out through one of the guys that was there. She's not a lesbian and as far as I know she's not bi nor are the 2 friends so I'm not worried about anything emotional going on there but I still just feel betrayed. Should I talk to her about it?

Can you summarize the given text in a few sentences?
<bot>: Girlfriend made out with her 2 best friends [also girls] at a party and I'm conflicted about whether or not it's cheating