sometimes things have to get worse before they get better.
I'll be brutally honest - if this was a woman posting about her husband not being able to get over his emotional affair the general consensus would be that she should leave him, that she deserved better and that he was a lying cheating w@*nker, and that the only way for the marriage to survive would be for him to totally cut all contact with the om.
This is no different, and tbh if your marriage survives this it will be a miracle, but marriages do survive affairs, both emotional and otherwise and if you do the right thing then your marriage might stand a chance, especially considering your dh is being understanding about this and has chosen to forgive you.
But you are not the victim here, your dh is.
Let me be honest. This other man doesn't love you. He may have told you he loves you, you may believe he loves you, but he doesn't. If he genuinely loved you then he would be with you, and he isn't. He is with his wife, who is apparently going through some "issues" - wake up it's the oldest clichet in the book.
He is a game player. Nothing more. You said he had looked for you, and yet when you found him he said he had feelings but that he wouldn't leave his wife. Presumably he looked for you to boost his ego. He knew he was the one great love of your life and he just wanted to satisfy his curiosity by finding out if he was still the one great love of your life, and you played right into his hands.
Well now he's had his kicks it's time to walk away.
I realize that sometimes people fall in love with other people and marriages end as a result. But this is not one of those times. If you were meant to be together you would have been together, and you're not.
Time to stop dwelling in the past and get on with your life, before it's too late.