Since you have told him you do not feel the same and you are happily married, the rest has nothing to do with you...if he chose to tell his wife and she left him, that is all about their relationship and their unhappiness. I would continue on with your life and not have contact with him. It sounds like he was not able to hear you when you told him you did not feel the same way, so maintaining a strong boundary is the way to go.
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