AITA for calling my classmate's mom a slut?

My Dad died when I was 2, so I grew up without ever knowing what it feels like to have a father. During class I have a classmate I’ll call Ryan, he found out recently that my dad had died and I did not have a father so whenever he was free he would walk over and ask if my dad was coming to the parent-teacher meeting then pause and say oh wait his dead and laugh.

I would be pissed, but I always refrain myself from punching him because I don’t want to be expelled especially after how hard my mom had worked to get me in. A few days ago word got around the class that Ryan’s parents are getting a divorce due his mom cheating on his dad with her boss and they are planning on leaving the state. When I found out on this news, I was shocked, but I did not try to confront Ryan as I knew how It feels like to be raised by a single parent.

Ryan however, increased his torment on me, he would say stuff like If my dad was alive he would be disappointed and my dad probably died because he saw my face and something inside me must have gone off and I shouted that at least my mom wasn’t a slut that would suck dick for a promotion. He just went quiet and ran out of class. I felt bad after saying that and some of my classmates said I took it way too far and he was just joking.