Wife Cheated With Boss

Long story short. Me and my wife are going thru couple therapy after she cheated with her boss for almost 2 years and also with a co-worker. We are trying to save our marriage. After i found out about her affair she went into severe depression and mental breakdown. I though about divorce but i truly believe that she still loves me and that she really is sincere. In the process of theraphy one of the stages we have to go throuh is about she telling me everything that happened so that there are no more secrets between us, so we can heal our wounds as a couple. The problem is that being there listenning to her telling me that she sucked her 60 year old boss several times in the office, in his car, that he fucked her inumerous times and all the details of what happened is getting my crazy horny. I wasn't like this, i didn't ever think about mynwife with another man before this happened but now i can't think of anything else. I came home after every session and as soon as possible i go to the bathroom and masturbate to the images of what she just confess... Its just so fucking obscene. I want her to be fine but at the same time i wish she just do it again...
I'm willing to tell details if yoy guys want to khow more. PS- sorry, english not my Mother language