I've been going with "friendly but business-like". I'm not interested in socializing with him while he's involved with someone else.

My H stands on the porch when he drops S7 off - he doesn't get invited in. However, I'm always pleasant and nice - I'm not going to be rude, but I don't draw the conversation out. Just "How was he? What did he have for dinner? Great, thanks! Bye now!"

H: 39, Me: 37
SD: 18, S: 7
M: 9, T: 10
"I love you but am not in love with you" - 5/11
Discovered online affair - 7/11