So I broke up with my ex of 7 years (9 years a few days ago of knowing him) after he cheated on me. We still sort of seen each other for a year after we played each other and tried to make it work etc and I finally broke it off late last year. I started seeing a guy shortly afterwards and it has now been 7 months. All my friends have asked me if I've had "the talk" with him so we know we are in a relationship and we haven't but it's been going well. Anyway I was away at the weekend for a festival and my ex was there and we ended up sleeping together. Now my ex thinks we should get back together etc and he keeps harassing me to let him know. But I really don't want to because I like the guy I am seeing currently.

I feel like I really need to tell him what happened between me and my ex, we haven't seen each other yet so I haven't had a chance. I will be seeing him tomorrow. What do you all think should I tell him or not or should I just block my ex from the picture and put it down to a drunken mistake. If I was to tell him should I say it was my ex or some random person?