Meddling ex

My son (age 15) asked a girl to a dance yesterday. My ex promptly freaked out (he’d sent me 10 texts about it at 6:45 this morning). Then he called the girl’s parents. The girl now can’t go. I feel like him calling this girl’s parents made us all look stupid (the dance is a month away). More importantly, I feel like it was a bit of violation of our son’s privacy, and that it will also make him disinclined to share info with us in the future. I told my ex this and he (as always) went off on me and then told me he’ll do it every time our son asks someone out and will do it with our younger kids too (this was mostly a “you can’t tell me what to do” tantrum on his part). He also said our son will never know that he called. I sort of think our son has a right to know what my ex did for future reference. But that also seems like a shitty, divorced parent thing to do (“look at what an asshole your father is”), and I’m having a hard time determining whether I’m wanting to tell my son for his own benefit, or if I’m doing it to punish his dad.