Bf disrespected my deceased father

My boyfriend and I went to eat after the gym and I was venting to him about my childhood and how I wished my father spent more time with us instead of working so much. It wasn't after I had my child I realized I had become my father.

He responded your dad was probably having sex with another woman and that's why he was barely home.

I responded "you better watch your fucking mouth. Don't ever disrespect my father. He's not like you (something from his past) or any of your friends."

My father passed away in 2018 and it is still a sensitive topic how me. I have always spoken great things about my father to him. I don't understand how he could possibly think saying something like that about my father is okay!!

Thought on this??