Hi Beth and welcome. Sorry you have to be here though.
I also just got a bomb this week that the A is continuing with H and OW. They aren't in contact physically but still have serious feelings for each other. I confronted H about it, but did it very calmly and only took a minute to cover it. H has told me recently that he is 'numb' to talking about OW with me, so I have tried to let up.
I don't know if you should bring it up or not. Where will it get you? Will he be defensive? I know H thinks I am snooping and he feels he has no privacy (this is NOT true, by the way) so he gets angry/defensive if I bring something up.
I think the 'pros' on here would say to not bring it up, not give OW the time of day. Be above it, be positive, be the beacon. You should give the air that you don't have time to be in 'his mess', that you are doing fine on your own.
Wow to the bullemia reference-very very true. Sad.
