"He had moved out and was living with his co-worker when he suddenly died of a heart attack while having sex. Divorce papers were never filed, no legal separation. They were in the process of moving all things legal. But on paper, they were still happily married."
Then the son shared what his mother did next.
"Well, my mom was hurt and petty and marked his gravestone as 'In loving memory of John Doe, son, husband, father and adulterer'."
He claimed that the act had left his father's family and new partner upset and asking him to intervene to remove the inscription.
"I personally think it's fine, that's who he was," the son wrote.
"He was all of those things. And since it's my mom's plot, I can't do anything.
"Am I the a**hole?"
Users reacted in support of the jilted mum, labelling her an "icon" and an "MVP" for her stance.
"Can she adopt me? I wish I had a mom this ballsy," one person joked
But some felt the mum had gone too far.
"Yes, he cheated and that's rubbish. But he was a living complex human being who's not even been afforded dignity in death," one person argued.
"Feel a bit sick reading these comments cheering it on."