Most Helpful Guy
I couldn't do that to a friend, I would be cool with it, but I wouldn't trust that friend.
Most Helpful Girl
Your ex's friend is not your ex. They are two different persons. My ex always said that if I liked his friend and we weren't together anymore, I should date him, because what if he is the one for me?
From my experience, my ex always told his friends about the "stuff" we did. Always made me feel embarassed when I was around with them, but not all guys are like that. Some feel just as embarassed talking about it.
But going out with his friend, just to make him jealous seems very unfair. Why would you want to make him jealous?