But the relationship is a dance. Just because the music is playing - doesn't mean you have to get out of your chair.
What triggers him is on him.
What you do is on you.
You aren't in control of his actions, and he will do what he will do no matter what you said to him. That is the point I'm making. Why compromise your own integrity and kindness and then beat yourself up afterward? Because you know that words hurt. You did it on purpose. That's what you can own, not that it in some way "caused" him to do thus and so.
The dance.
He put the record on, and you jumped out of your seat to dance with him. So the dance continues. You hurt me, I hurt you. You hurt me, I hurt you. Tit/tat.
Someone (one of you) needs to put on some headphones and not dance. It takes two, and he's still tango-ing away.