Look, my pen pal is a married man and we talk about everything. I like him but know we will just be friends. If you set boundaries and limit the amount of contact, there is nothing wrong with being in contact with a married man. If he is interested in more than a platonic relationship, well, that is a different story. I talk to different men too, not just to this pen pal who is married. I like him a lot too but know that his marriage is his choice and responsibility. So, if you tell him how you feel about not wanting an affair and like talking to him, I don’t see any problem with interacting with him. You say you are falling for him in your op,. If this is the case, then I would try to distract yourself with other interests or people. Most married men who have affairs don’t leave their wives. They just want sex and if this is all you want too, well, I am not one to judge. You are your own master!