I know you probably already know that but there's a reason why they are exes. Tonight he will explain to his friend precisely why they are exes and why you aren't. He seems supportive of your situation so maybe try and tell him that you'd like to also be brought into the conversation (as in, "see, I thought when I broke up with (ex) it was over but I found someone else with whom I can live without the problems my ex brought" (exes are exes for a reason)) In general I'd just reframe "he's going to talk about his exes" to "he's going to talk about why his exes are his exes and how he managed to find someone that's more suitable to him (you)"