Throwaway account just to be safe. Names are changed but ages are the same.

I am a 26M and my older sister Julie is 28F. Julie is married to Tanner, 29M, and they have two kids that are 6 years and 5mo old. I have been best friends with Kyle 26M since we were in diapers. Kyle is engaged to Cathy, 28F, and have a wedding date set in November. Cathy and Julie went to high school together and have been close friends for years. Kyle and I both work at a gym that Tanner owns. We all live in a town with less than 2000 people that live here.

2 weeks ago I was out with Tanner getting lunch before heading back to work, when Tanner started to swear while looking at his phone. He showed me the phone and while looking on his baby camera app, Tanner saw Julie and Kyle kissing and getting intimate. Tanner started yelling at me asking if I knew about it, where I was in shock and told him no. Tanner started taking screenshots of the images and said he was going home for the day. That night he ended up confronting his wife, my sister, Julie. She admitted to having an affair with Kyle, my best friend, for months.

Cathy was out of town that night but Tanner called her to tell her what was going on. Cathy came back the next day and immediately called off the wedding and kicked Kyle out of the house. Tanner took the same route and also asked Julie to leave the house so he could think over how to go about separating while also keeping the children in mind.

A few days later Julie and Kyle decided to move out of our town and to a town 20 minutes away and rent an apartment together. Two days ago I helped to move them in and I am getting a lot of heat from Tanner and Cathy. Kyle is my best friend and Julie is my sister and I know what they did was wrong but I also know that they don’t have a lot of support at the moment and they are both family to me.

This takes us to today. Tanner is now telling me I am not allowed to see my niece and nephew since I decided “cheaters are more important than him”. I also lost my job today, where Tanner was my boss. I am stuck in the middle where my best friend and sister were the ones who had the affair but Cathy has become like family as well as Tanner and my niece and nephew.

I am stuck in the middle of the family drama as I am the single one of our now broken friend group of 5.

Edit: For clarification on the moving process, I was helping my sister move out of the house she had with Tanner and move into her new place and found out while helping her unload that Kyle was moving in with her as well. I took everything out of my car and left. I haven’t talked to them since.