Before I didn't really negotiate a deal. I just said I was taking him with me, that everyone else was in couples and I didn't know them, and that his daughter would be my priority as it is her party. The reality is, that it will be fine, but he gets himself so wound up with "what ifs..." that, in his head, become certainties...
My son is ok about seeing him again. He'll be seeing him on Saturday night, too because we're all going somewhere together, but they will be sleeping at their dad's as it is actually his weekend. I think last weekend felt huge to him, but this weekend, my boyfriend will be joining us on something we're doing, rather than us going to see him. I think my son feels more comfortable with that.
redundant I think you need to accept that they are talking to other people. That's how it works. So it's not a case of how would you feel, but how do you feel.
Don't put all your eggs in one basket, and all that.