My LTRs best friend's ex messaged her ln. The best friend and the ex are still close friends

The guy said that to my LTR she should come over to his and he wanted to fuck her.

After she declined he said he was only joking and she shouldnt tell anyone. The guy is some big time drug dealer in my area and people are afraid of him. The guy knows me and we have met several times.

The worst part is she told him shes not going to cheat on me and he told her "I can make u cum better than him"

I told my LTR to block him and she did. I also told her that if her best friend gets back with him she should next her best friend otherwise im gone.

Did I handle this correctly?

I'm considering nexting her over this but I am in 2 minds as to whether she did much wrong. She thought he was going to discuss the ex relationship with her best friend with her and wanted to help fix their issues.

But idk if im just being a massive cuck faggot for beleiving this. I've read the convo and it is exactly as she says.

Part of me thinks she was entertaining the idea of sex by keeping the conversation going.

Thanks