In her drunken state she confessed that in the past she has flirted with some men at work and had often fantasized about a particular ex coworker pushing her into the bathroom at a bar she used to go to for happy hour and having his way with her. She told me she often thought about it when we had sex.
I kind of wonder if this is really just a fantasy haha... The fact that she is frequently envisioning this same scenario during sex makes it seem more like a past experience. I mean, at least for myself, I had an... indiscretion... a while back and it's something I frequently think about during sex. If my wife told me now that she was really into sharing me, I have to be honest, I would probably describe it to her as a fantasy, not admitting it was something I'd already done before I had consent.
If it is more than a fantasy, you wife may have a mixture of arousal and guilt from the experience (as I do), which could make her hesitant about repeating it, even with consent.
I think also, even if you wife has or still is fooling around, there is a barrier to sharing it with the husband for fear that, despite all the reassurance, it will evoke jealousy / anger. I know for my wife, probably the last big issue is that she is afraid of how it could change things, how I might react to the reality of it and also that she might not be able to go back / things could get out of control once she crosses that line. She said "it's already hard for a girl like me to always be good."
I myself am not exactly sure where to go from here since, while I do want to share her, I do also have concerns of things getting out of control given her personality and that I am looking for more stag / vixen / MFM action, not to be left at home constantly while the wife is our banging. So now I'm a bit afraid to push things, lest it play out in the wrong way.