<human>: I'm absolutely in love with my girl, and I believe her when she says that she is too. A co-worker and good friend of hers seems to be in to her, this makes me uncomfortable. I'm definitely the jealous type.

For the longest time I tried to avoid checking her messages, because I feel like its a breach of trust. But today i did, and sure enough, she's talking to this friend a lot. it's mostly friendly banter, she says that after she leaves her job she wants to keep hanging out with another (female) coworker and him. He seems to be flirting with her.

Here's the thing: I asked her what she's been up to while I was away (we talked daily of course) and she mentioned nothing of seeing this friend. But it seems like this friend met up with her several times. and at one point told her that she can come over to his house for coffee, to hang out, or to sleep (wtf!?). I know they met up to study at the Uni at least twice.

My GF insists she was studying by her self (I aksed without being confrontational). I don't thnk she's cheating, we're always together when I'm in town and she literally has no time to cheat. 

My best friend (M, also her good friend) says she just didn't want me to find out because she knew i'd be jealous. told me to forget about it. But the lying really hurts.

What do I do? Should I confront her? Was it out of line for me to check her texts?

Could you distill the essence of the text into 1-3 sentences?
<bot>: Found strange texts on gf's phone, although they dont suggest cheating it hurts because she lied about them. Do I mention this to her?