May, you are doing so well. I don't think you think you are, but I think you are.
Yes, I was the HD partner in a SSM and to be honest, that made the EA ten times worse for me. There was physical attraction there, expressed to each other, and it wasn't far off from becoming a PA. I was totally dumbfounded that this man who had said some version of 'if only I wasn't so tired, you know I'd want to, but it's just impossible right now and I'm as frustrated about it as you are,' for literally years had found the emotional interest and desire and time for someone else.
And you know, as the SS wife, when I found out about the EA and he became scared of our marriage ending, shocked at what he'd done, and eager to make it up to me, I used it as a lever to get him to be close to me. You'll remember we went to MC for six months after I found out (I forced him) and while he blamed me for it the entire time, he also took lots of care to flirt with me, woo me, cherish me, come to bed with me - all of that - for weeks and weeks. And I really jumped on the 'guilt card' and made sure whenever I felt like being comforted, he knew he owed me that. And it was I think really awful for him and part of the reason he left was because he couldn't stand the idea that my forgiveness rested on him never having his own space, never being able to say, 'right now you have to deal with your own feelings.'
Perhaps this is too far away from your own experience to be useful to you, or perhaps it sheds light on your changing dynamic.
