Apology Letter For Triggering You

Dear {Recipient},

I'm really sorry for triggering you {yesterday/this morning/etc.}. I should have known better than to talk about {topic} in front of you given your past trauma. Please forgive me for being so insensitive.

Is there any way I can do right by you? I really feel bad for causing you to {have a panic attack/other symptom}. How about we {grab lunch/catch a movie/etc.} {later/tomorrow/this weekend}? It'll be my treat and I promise I won't bring up anything negative.

Best,
{Your Name}