Well Stuck, I had lost desire for him. And it was not him being with OW that turned me on. It was the separation and me not feeling the weight and burden of his misery upon me. I at least felt like I was f*cking a grown up.
The OW thing hurt and still is the most compelling factor in my inclination to file. Him having sex is one thing but a GF? When all along he was throwing me breadcrumbs? Devastating.
My sitch is different of course but it is important to do what is right for you and not try to manipulate her. You can't know how it will be interpreted.