Does he know that you know?
I would be so so tempted to give him a "knowing" smart a$$ smirk when I saw him

That would make anyone squirm!
Yeah found his number I called him directly and confronted him about it. It was the 10 most awkward minutes of him telling me to talk to my ex-wife about it. I just basically told him if nothing happened just tell me instead of stalling so much.
Then I told him he had no integrity for not telling me the truth and that was it. I didn't feel good it was awkward for both of us =(