Need perspective on this situation. So I went to an EDM concert with my gf this weekend. It was her guy friend who I never met before who invited her. Now, this guy is married and his wife was there too. But all of them took the drug Ecstacy, as is common to do at these concerts.

At one point, we needed to walk across the venue, and the guy grabs my gf's hand and leads her through the crowd. I'm holding my gf's other hand as we try to make our way through the crowd. His wife was somewhere else so she didn't see. I also saw his friend give the guy friend's wife a massage. Should I just chalk this up to everyone being under the influence of ecstacy? Also when they were talking, at one point he had his hand on my gf's upper waist/side. There was another one of his friends who also held my gf's hand for a bit to take her to buy drinks. Again, I was following behind her, holding her other hand.

After the event, the guy friend texts my gf some stuff, and says "You look prettier every time I see you." Lol. This guy has a wife and he's texting my gf this? Also he just invited my gf to go to Vegas with him, his wife, and his friends to go to some 3 day EDM festival. I'm kind of concerned that the friends might try some shit when I'm not there. I was there this past weekend, and they still openly held her hand. Imagine what they would do if I'm not there. Am I right to feel uncomfortable? Should I let her go to Vegas too?