Yoga I think Snapes suggestion as to a reply sounds like a good start. I'm sorry, again I've been in a similar situation, in my case the OW and STBX are no longer together but for reasons which I can't go in to, the DCs still need to see OW on occasion. It has got easier over time, I'm trying to remember how I coped the first few times and I think I just focussed on how the DCs had been with (eg. had they had a nice meal, or whatever), then went and pulled up weeds with a vengeance.... And SoSweet and Fayster's advice is wise....it is very hard sometimes when my DC just seem to idolise their dad.
Western I'd be having exactly the same dilemma, I have no idea how to play these things, and actually no desire to play games, so I'd just reply as Yoga suggests, and then wait and see!
I have a mini dilemma of my own. Have exchanged quite a few texts / emails over the weekend with sort of colleague. Beginning to chat about stuff other than sport, work and news. Nothing risque, just chatting back and forth quite a bit. Asked him about family, he replied that he had a child from his 'previous marriage'. Hhmm. Is it just me, or does that sound like he has since remarried? Because he has never mentioned a partner, and if he has one, then that's it, obviously, and I don't care if the mid week drink is even vaguely work related, we can discuss it in work time as a strictly work matter if it is! Anyway, I replied asking how old his child was, and how long he'd been divorced, and I haven't heard from him since then....suddenly everything went quiet! Bum. For me it's been a huge reminder of how STBX would begin his affairs with the OW....
It's made me think I am probably not ready for dating after all. I may just stick with aquiring hundreds of cats, as per the original plan...