Mine did the same thing, for a short time. I couldn't cut off contact completely because of logistics involving children/finances, etc. So, what I did was make my boundaries clear. We will talk about children and finances and other necessary topics, but not personal circumstances, our relationship, etc.
Then, whenever he would start to go there, I would end the conversation. Gotta go, bye. It took a little while of repetition, but it finally sunk in and he stopped going there.
Good luck.
L