<human>: For the first time since we've been together( and we live together), I snooked on her facebook as she left it open before she went out. I saw some "shady" messages as "I love you, miss you, cute nicknames etc to her ex'es that she's good friends with. ( I do think she talks to a lot of people like this, so I don't think it means anything).

Then I got curious, and scrolled up, where they talked about a party they had been to, and the person she was talking to said vaugly  that she had made out with a guy, and said and done some questionable things( I don't think it was sex). But she didn't want to talk about it, so the conversation ended there. 

I don't know what to do. I invaded her privacy by looking at her messages, and I feel bad for that. At the same time I want to confront her, but then she'll get trust issues as I looked at her facebook without her consent?

I don't want to break up with her as we live together, but she hurt my trust as she didn't tell me about it. (She even told the guy on facebook she told me, but she never did..)

Could you distill the essence of the text into 1-3 sentences?
<bot>: Girlfriend and a friend of her talked on facebook about how she made out with another guy when she was super drunk. I'm not sure how to respond..