I know I shouldn't have done it, and I wish I could unknow what I now know... but I can't.
In DP's archived FB messages was a message from a girl complaining about how he'd had sex with her in a toilet and then left her there. He apologised, saying he was very drunk. I looked back and all the dates match up with my text messages so he definitely did it. This was three days after we made our relationship official. 
What the actual fuck do I do? I'm trying to act normal while I plan but I'm shaking and don't think I can hide it much longer.