There is likely something unsatisfying in your marriage or you’d never think you two could be great together. People in happy marriages don’t think this way. I never ever think that I and some other man would be great for me. But when I wasn’t in a happy marriage/relationship, I sometimes thought that some other guy would be great. What’s happening in your marriage? Can you work on that?

My suggestion is to completely cut this man off with zero communication
that might mean leaving your job OR perhaps consider ending your marriage so you can look for a better fit.