I posted this in "Just Found Out" but I am sharing it here too in case it helps anyone else.
Dear A.P.,
Here is why you don't matter:
It's not because of your weight. My biggest hero and role model was a fat women and no, you don't get to know who she was because you don't get to know me.
It's not because you are promiscuous. Most people with an "open marriage" have ground rules. You, apparently, do not.
It's not because your writing in your e-mails is sloppy and grammatically incorrect. Some of my favorite songwriters and poets use incorrect grammar. But you are banal. My husband's communications with you were trite, predictable, and boring to anyone not reading them to discover a betrayal. They were of interest to me only in that they were proof of my H.'s actions.
Every second that my husband spent with you made him a lesser man. His entire relationship with you was based on lying to the woman he loves. (And yes, I believe that he loves me even though he is a deeply flawed person capable of profound duplicity.) I have no idea if your behavior with him made you a lesser person because I don't know you. You actively and repeatedly participated in a man's decision to become a a lesser person.
Here's another thing: You are still lying. You expect me to believe you never had sex with my husband. it did not occur to you that he might actually have enough respect for me to finally tell me the truth. You think he is still choosing to be a liar.
He has told me he regrets every moment with you because of what it has done to me but also becuase of what his choices have made him become. It's been established that my husband is a liar. Is he lying now? If so, he sure is willing to throw you under the bus to rescue his life with me.
I have come to the realization that I love a deeply flawed man. You helped him to become this worse version of himself. He is trying now to slowly repair the profound damage that he has done to me and to our family. Will it work out for us? I don't know and you don't get to know.
Because You. Don't. Matter.