Currently on holiday with my gf (20f) in Greece. Yesterday she wore one of her smaller bikinis to the pool and we were drinking throughout the day. There was a group of boisterous older gentlemen at the swim up bar who we begun talking to, but after a while one of them started making slight inappropriate comments about how my gf looked in her bikini. He said she was being a bit of a show off earlier when she was kneeling over in her sunbed to stretch, and that being in Europe some people may mistake us for swingers or nudists. He also said he thought her body looked as tight as one of his daughters friends. We continued drinking with them anyway as they were fun, and later on invited them to our room to play some cards. When we went up two of the other men excused themselves so it ended up just being the one coming back to ours. The odd comment kept coming still and my gf was in a giggly mood despite him being quite an overweight man and at least 30-40 years older then us. A short while later she excused herself to the bathroom and came back in with the lingerie she bought for our last valentine's. Things got handy quickly which I was okay with as I thought we were maybe going to have a threesome. But the man started pushing my hands off etc. He said that I could watch but only if I put on a pair of her panties and sat in the 'cuck chair' in the corner. Seeing as my girlfriend didn't make a move to correct him I was forced into this course of action, and despite my complaints had to watch as he used her with no limits. He ended up cumming in her asshole then abruptly leaving without saying much else, and I could see cum dripping out of her hole down her leg as she let him out the door. My gf has been acting like nothing ever happened since yesterday and I'm not sure what to do.