your ex and her new bloke?

Last night i went to my friends house warming party and my ex (we went out for 6 years and were supposed to be getting married in September) was there with her new bloke (who she evidently finished me for)

I haven't seen or spoken to her for a month (since we sorted out the last crap with our joint account/flat) and i have never even met this cunt of a new bloke, but the first thing she did when i arrived was bring this bloke over and introduce him to me like we could be really good friends 'if we got to know one another'

Anyway i told them both to fuck off and left the party immediatly.

My ex then rang me and accused me of being childish and petty and told me 'Its about time you moved on, we can all be friends'. I hung up.

I personally don't think my behaviour was that unreasonable but having spoken to a couple of other people this morning it seems that the a few people think that it was.

Anyway the point is my ex and I have the same circle of friends so unfortunatly i will be seeing her and this bloke around quite a bit in the future. Is it possible to be friends or should i just sit in the corner at parties and throw them both evils?

Sorry for the long post - have a good Bank Holiday