I'm 37 and she's 35, together for a bit over 2 years, living together. Recently she was showing me something on instagram that someone DMed her. While looking for it in her messages, I noticed a name of a guy I haven't heard about. Asked who that was and she said it's her colleague from work. She said they just send each other some funny reels from time to time. She opened the chat with him and quickly scrolled through to show me. While doing that I noticed some text exchange and asked if she can pause. She did and what I saw really surprised me – the guy said they should go for a beer/whisky (her drink of choice) catch up – to which she responded that it's necessary and she will let him know.
She claims that she didn't have an intention of going out with him (and didn't go nor made any plans) but she didn't know how to respond. Also states that the guy is older and has a wife and kids. She also mentioned that they went out a few times with her two other girlfriends from work and him. She says that this guy didn't have any other intentions than just to catch up.
While I want to believe what she is saying, it also doesn't feel entirely right. Any tips how I should interpret and handle this situation?
Thanks!