One last hoorah.. with my ex

It’s a bit interesting how it all fell into place but. It is what it is. My fiancé and my ex (short term girlfriend) from a few years back are best friends. They went for dinner and drinks with their girls early on and then called me asking for a ride. After picking them up I realized they where already pretty intoxicated. My fiancé got in the front seat and I got out to move some things so my ex could get in the car. It was pitch black out and when she got in the car her hand grazed the front of my pants as she was getting in the car. I thought noting of it and we went out to the bar. My fiancé and her friends where out on the dance floor having a blast. I went out to the car for a smoke and not two seconds after I lit one up my ex came out and asked for one two. Just me and her alone. We talked and went back inside to drink more with the group. Fast forward and we’ve now left the bar, we get back to my house and my ex says she can’t drive and ask to stay over. My fiancé giggles and says that’s no problem the spare room is clean. We go our separate ways and get ready for bed. My fiancé falls asleep and not 2 minutes later I feel my phone vibrate. Text from ex: umm where are your towels, I’m taking a shower. I respond: I’ll put one outside the door.