AITA - boyfriend (33M) pissed at me (29F) for messaging my ex.
Went to a comedy show the other night with some friends and happened to spot an ex boyfriend & old friend. Ex was on a date. We ended up with tickets right next to each other. I sat furthest from him out of my group to be respectful to him/his date. He didn't see me, but I messaged him afterwards. He is the kind of person who would absolutely give a friendly hello to an ex (and did to 2 of his exes when we were dating). We laughed about the coincidence and then enthused about the show. Nothing flirty at all. We left it there.
For context- ex was my best friend from ages 14-17. I grew up in a very abusive home, and he was a really supportive friend through some of my darkest times. I had a bit of a teen crush on him but nothing came of it. We reconnected in our 20s, dated briefly, but ultimately weren't suited to each other. It ended amicably. We acknowledged the bond of friendship in our teens and agreed to remain friends. It was left there - happy enough to incidentally cross paths, appreciative of each other, but with the chapter respectfully closed. We've touched base infrequently if something pops up (e.g. on Instagram or through mutuals), but have let the distance be organic and respectful. We've both moved on romantically and had fulfilling relationships since. The last time we spoke was two years ago.
I am now dating a great guy - very happy and very in love. In the spirit of honesty and transparency (I've been cheated on in the past),I told my boyfriend I'd seen an ex and msged him after and had a laugh. Boyfriend was taken aback, took some space, then sent a super hostile message saying that he "couldn't care less" that we were once friends, that he couldn't understand, and that my actions were "blatantly inconsiderate, demeaning, and outright disrespectful".
It's okay for him to have feelings about this, but I'm pretty pissed at his reaction tbh. It feels inflammatory and like he's attacking my character and morality rather than addressing the issue, and doesn't have any room to understand the full picture.
Wanting some perspectives/advice.
What's considered normal contact with exes?
Do I have a leg to stand on, or am I just being defensive?
AITA?