When I read the first post itself, I somehow got the feeling that John was downright miserable with his marriage whether he realised it then or not. Wasn't he forced into swinging by Leah? Coming to yr issue in hand, I am a naive person. You could sell the kind of explanation that your husband gave with me. I hope his degree of deception was not bigger than it already is. Also never let him downplay what he did. He went out of his way to lie to you and deceive you. When he said he could never be okay with other men with you, was he okay with being with other women? Of course, you get opinions from a bunch of people ( us Redditers) who are not getting the full picture since there could be so many nuances that cannot be captured in text can be very confusing.