I (28F) walked in on my best friend (32F) having sex with my boyfriend(31M).

I am in complete shock. My boyfriend was supposed to pick me up at 8 so I could meet him up so we could go see a play. I had an hour to kill before I had to go pick up the tickets, so I stopped by his house to hang out for a little bit. <br><br>When I walked in, Rachel was riding my boyfriend. I froze and burst into tears, my boyfriend jumped off the couch and so did Rachel. They were in complete shock, Rachel screamed "I'm so sorry" or something like that and she ran out the door.<br><br>I ran out the door as well, I walked down the street while sobbing. I finally stopped and called an Uber to pick me up. I went to a park, sat on a bench, and cried and cried and cried. I just cannot believe they did this. <br><br>I've know Rachel since I was 15 when she was 19. She was a foreign exchange student from Germany who lived with my family. She is one of the kindest people I know. I was even thinking about asking her to be my maid of honor. <br><br>My now ex-boyfriend and I have been together for 3 years. He's always made me feel like a princess. He's also made me feel like I'm the only person in the world. <br><br>I don't even know what to say. I feel like I've lost not one best friend but two. My fiancé and best friend. <br><br>I don't know what I'm going to do, but what I do know is I'm never going to be able to trust anyone again.