So long story short last night me and my boyfriend were both at our separate friends house having a drink and watching the football the plan was to get a taxi together back to our house. So then night went on a girl I know messaged me saying that my boyfriend had tried to add her on Snapchat thought it was a bit weird but asked her to play along as I have had suspicions for a while and wanted solid proof he would cheat. They arranged to meet up and the girls told me he was meeting him at this place at this time and I was their and he turned up to get her and I caught him right out. The messages he had been sending her prior were very inappropriate and they agreed they would be meeting for sex. Now obviously I am so so hurt by this he says it was down to the drink and he's so sorry I don't know where to go from here: