I would pick one of two paths to take. One, if you are concerned, tell him you can meet him for a short period of time, and make sure you leave when you said you would have to. This way you control at least the time, so if he does start rambling into how great OW is, you can listen, smile, validate, all the good DB stuff, but you will not have to do it for very long. If it turns out to be a good conversation and good news, still end it, but you can make a comment as you leave like 'this was nice, we should do it again sometime'.
My other choice, if I was a girl who was looking super hot, I would meet him at a bar that was full of guys who would hit on me. Trust me, guys will be watching if it looks like your H is annoying you, and will be more than happy to strike up a conversation with you while walking to the bathroom or something like that. Let your H see others fighting over you and it will cut him like a knife.
Best of luck!
Me: 42 W: 32 Married 7 years together 8.5 S1: 7 S2:7 Bomb #1: 09-16-13 Recon #1: 11/13 A discovered 04-03-2014 W filed D 05-19-14 but never served me I filed D 12-02-2014 S 05-31-14 Divorced 5-19-16