How to deal with an ex on a night out?

I’m stuck in an awkward situation here. My best friend and her boyfriend set me up with his best friend and things ended badly. We were supposed to be seeing each other and he said he seen us as being a good couple but through my own fault he basically just used me for sex then left me for his sisters ex girlfriend who used to be a lesbian, he seen her for a few weeks then moved on to another girl. My friend, her boyfriend and I are all going out to a club tonight for a party and my ‘ex’ or in other words the guy I was seeing is gonna be there and I don’t want things being awkward because I’m still really angry with the way he’s treated me but can’t really tell him he can’t sit with us because his best friend, my friends boyfriend is gonna be there and I don’t wanna make a big deal out of things. Any advice on how to deal with this awkward situation? I feel like we should talk things out and agree to be friends but I don’t know if that’s what he wants since he blocked me but he knows he’ll have to see me from time to time. I HAVE NO FEELINGS FOR HIM ANYMORE