<human>: Can you provide a brief overview of the text?

Background: We went to high school together but were part of different social circles, after graduation on a whim my friends invited him to go camping with us (some of my group were friends with him), he said yes and that was the beginning of our relationship and his integration into my group of friends. They are now pretty much his only friends

Now he broke up with me in October and while it's been hard (we dated for two years) I like to think that I've been coping and am starting to move on, there's been completely no contact since the breakup. But the thing is we share the same group of friends and I know I'll have to see him eventually, which I'm starting to come to terms with. However, he came clean to our friends about a month after our breakup that he was dating the girl that I essentially blame our breakup on (This is the same girl that he told me I had nothing to worry about when we were dating). 

He's introduced her to our friends and I know that he will want to start inviting her to do things with the group (ex: My friends birthday is in a couple weeks, and we are going clubbing and he is invited and he will undoubtedly invite his new gf). I am not okay with this. I can deal with having to be social with him but not this girl that I blame for causing our breakup. 

So I guess my question is, do I have a right to tell our friends and him that I will not tolerate her being around and that I don't want her invited to do things with us?
<bot>: Do I have a right to tell my ex-boyfriend and our friends that I don't want his new gf (who I blame our breakup on) being invited to our group activities