Sorry you're here but you're in the right place. You also seem to be handling this quite well.
I have read that when the bomb drops they don't want to be around us, they want to be alone. That's why they leave. Try to suppress your desire for "face time" with your H. I would make myself scarce if I were you. focus on you. Get a life. Get a new hair style, clothes, perfume, hobby, etc. Become mysterious.
Don't tell him you love him, boys are hurt, home is where he should be, he's making a mistake, etc. These statements will only make him feel bad and cause him to avoid you even more. He has to figure this out for himself.
OW is a distraction. She is a playmate. Someone to have fun, run away with. Let him go to her, let reality set in. It has probably lasted for two years because there was no reality to that situation. It was all fun and games. One day he will be with her, her children, all the pressures that entails and he will look over and see you. The woman he fell in love with years ago. Getting a life, better than ever, moving along without him, fancy free. You will be the OW and he will return to you.
"Fear is the mind-killer" Muad'Dib Me 53, XW 44, DD 14, DS 12 Bomb and OM 12/15/06 Separated 01/02/07 Divorced 05/13/08 X married OM(OMH) 08/2009 Married 06/09/13