How to Have This Conversation? Am I being insecure?
TLDR: My long-term girlfriend wants to hang out with a guy I think is creepy and I don't know how to approach the conversation about how I feel with her.
Hey 35m been with my 38f for about 10 years.
I'm not great at putting my thoughts on paper so bare with me.
Things have been a bit strained recently, we moved cross country for her to start a new job which has turned out to be incredibly stressful, and at the same time my freelance work has dwindled. I'm definitely not in a great place mentally. my self esteem/confidence is a bit low and my anxiety levels are high, hence looking for an outside perspective.
So here's the situation. There's a guy she used to work with, she describes as a lonely alcoholic. She seems to think his intentions are plutonic, but I'm not so sure. He's done a few things that seem a bit weird, like asking her to be his plus one at a wedding. He also seems to be willing to go to quite some lengths to see her. I've always said he seems a bit weird but she reassures me he's fine.....
He has friends who live in the next town over (to were we live now) who he visits sometimes and he asked if she would want to hang out with them when he went to visit. So she went to hang out with them. I didn't get invited, didn't really bother me at the time. Crucially, that time she got the bus home (I did offer to pick her up). Anyway. Soon after he invited her again, but this time he suggested she stay over. She told me this immediately and I said it was a red flag. She kind of blanked him for a few days and he said something like "that was my friends idea by the way". I don't buy it, she does. So at this point in time, I'm pretty sure she's planning on staying over at his friend's house next time they hang out. I don't know if I'm cool with this. It just seems weird, they're house is a short taxi/bus away, I have also said I'm willing to pick her up.
To be clear, I trust my girlfriend, she is not the one I'm worried about, I don't think she's going to get drunk and fuck someone else, especially not this guy, for a start he doesn't even sound very attractive, but more importantly, she just isn't that type of person.
What I'm more concerned about is him. We all know what some men are like, especially lonely ones. I'm worried that she will trust him too much. Like when he goes to the bar and gets a drink, he could easily slip her something and then what? Nothing good that's for sure. I would feel awful if I just sat back and let something like that happen, but also, she's a grown woman and I'm not usually in the business of telling her what to do.
The thing is, I'm not sure how to talk about this without it back firing. I'm essentially saying I don't think she has very good judgement/is naive/stupid and I'm worried it will come off as controlling (maybe it is controlling?) and me just being insecure (maybe it is).
How should I approach this situation? Part of me feels like I should just ignore my worries, it'll probably be fine, I'm just overthinking it, another part of me wants to put my foot down and say absolutely not, why would you even think of doing something like that and another part of me wants to demand to meet him/know who these other people are and the address she'll be staying at.
As you can see, with my emotional state, I'm not thinking clearly. I know we need to talk, but I don't know how to go about doing so in a way that's respectful of her autonomy and won't end up in an argument.
TIA, hope this isn't too much of a ramble.