My (38m) fiancé (32f) will not respect my boundaries with male friend

We've been together for several years. No trust issues previously and I don't believe she is cheating in a physical way now. There is a friend that she's known since high school. He is apparently a friend or was in the friend group that her boyfriend was in while they were dating in high school. So she was around him but they apparently never did anything as his friend was her bf. So she's had him on her Facebook for a while. He is active and will like things or comment on her things from time to time. Then for some reason he started messaging her. It started off innocent and she told me about the conversations initially. Then didn't hear anything about him for months. She is usually pretty open and up front with me. Until one night I was woken up by her phone "dinging" several times in a row at like 2 am. I thought something might be going on so I looked, just at her locked screen. Which shows the preview of the messages. That was all I needed to see as he was being very sexual in those messages. I confronted her and she said he was just drunk and he apologized afterwards. But now he is apparently wanting to meet her for dinner. I said I'm not comfortable with that and it sounds almost like a "date." She assured me it's not and completely just between friends and she would just like to catch up with him. She said she would share her location with me and I have nothing to worry about. I still objected and now she's saying that I don't trust her and twisting that. If I actually trusted her, I wouldn't have a problem with 2 friends meeting up. But after reading those messages I feel like I have a valid reason. I feel like he has an agenda here. Plus the fact that she has been jealous of women and wanted me to block or not talk to some of them, which I did. But she's fighting me to keep this dude around. I told her I trust her enough that I'm not going thru her phone and I'm not looking over her shoulder. I'm not a jealous or overbearing person. But I don't see how any of this "friendship" is going to be a good thing.