He wants to get back together but I don't think he knows
Most Helpful Guy
As long as those people don't know him or you haven't been video taped or pictures taken while doing so AND your sense of 'morality' can handle it, I'd say keep it to yourself. Especially since one can never be sure how the other person may react and also that since he's your ex and you guys are planning on getting back.
However, you know your situation better, handle it judiciously.
Good luck :)0