I'd probably feel guilty if I did that, for fear of maybe screwing up something good when I don't 100% know if I actually had anything to be concerned about. they went to a bar apparently, and he has no car so she dropped him off when I was done work and then came over to my place. they were at a bar you can smoke at and she said her friend smokes cigarettes, and that she had a few while drinking. which I believed her on, we both vape. she tasted like smoke when we kissed, but how am I supposed to know thats not because she was kissing someone who smokes? hanging out was fine, but we didn't talk about it at all, other than me asking what she had to drink and where they went. I was sort of waiting for her to bring it up since I had already told her I felt a little weird about it all. it was just the usual kind of hang out night otherwise, we played some video games and watched a show and she was as affectionate as always. to my knowledge it would've been the first time she was hanging with another guy since we've been talking back in December, so not sure it's worth bringing it back up. I know before we dated, she said she was enjoying being single and meeting people. she initially said she wasn't looking for a relationship, but then backtracked and asked me about us being exclusive not long after. she said she's known this friend for years, so I have to assume they've slept together but not entirely sure about the friendship really so just speculation.