Unhook yourself from the affair for a set period of time.
He loves you. He loves her, too. He can't make up his mind.
Set a date to re-evaluate if pure GAL works or not.
Im my sitch I thought W was only in EA with W, but it was PA. My wife revealed it was a PA after she broke it off with OM. She wouldn't, however, re-commit to the marriage, so I refused to buy a house until we were on more solid footing. I also asked her to get tested for STD and she blew a fuse. She wanted a separation, which I refused.
Boundaries test the heart of the WAS. After I refused to buy the house, she re-connected with OM.
I suggest for your own sanity, set dates and evaluate. If things don't improve, ramp up to Going Dark/LRT, if nothing changes, then ramp up to strong boundaries, if that doesn't work, then go for ultimatum. This is for your sanity.
I've read your situation from the beginning. I've got some observations. If you want to email me about it: theoden.king@hotmail.com