<human>: So I (M21) made this account specifically for this post. I don't want my girlfriend (F18) or I to be recognized through my regular username. My girlfriend of seven months and I are going through what appears to be a small dilemma, but I want other perspectives. She is currently attending an art school (we are both in college). She was asked by a friend to nude model for an art project, she has done this once before while we were dating and I was alright with it then, and I was alright with it this time as well. My only concern was that a friend of her's (a male) would be there. He is a friend of mine as well. She assured me that he wouldn't be there, so I didnt care that she was doing this. So she went to the modeling session, which lasted only a short time but while the session was rapping up the friend (who I didn't want to be there) walked into the room. I was not present by the way. He saw her naked, but only for a short time. This would have upset me a bit, but the problem is that when I asked her who was there she initially denied that he (the friend) was present. Latter she felt guilty and admitted to me that he showed up, but claimed that she was only trying to protect my feelings by lying to me. I know that she didn't expect him to be there and didn't want him there. I just don't know if I can trust her anymore and feel betrayed. I love her very much but feel hurt that I was lied to. What do all of you think of this? Is it a reason to end a relationship? It's really bothering me so I would really appreciate any advice.

Can you succinctly summarize the text in 1-3 sentences?
<bot>: my girlfriend lied to me about a male feind seeing her naked. I'm not sure what to think or whether I can believe her now.