Divorced relationship type gone

My male sim married another male sim. The two of them decided to have a divorced after my sim caught his husband having woohoo with his gym buddy.

Now his ex-husband, if you look at the relationship type, there's "best friend" and "divorce" and "it's complicated" when I hover to that sim. When my sim got past the 5 stages of moving on, and I hover to his ex-husband, I am surprised that the only relationship type there is "acquiantance". So I tried to flirt him back, but it doesnt work. I believe it is still treating him his ex-husband but it doesn't show when I look at the relationship.