It's kind of like whether or not to wear the wedding ring.......most see it as a personal decision. All of us probably have a view point about it, including me. I will save you the time of hearing my detailed opinion, b/c I think you'll probably do what you want to do, regardless of what somebody else says. Just bear in mind, you don't know what/who made her horny, but it wasn't you. Maybe that does/doesn't matter to you.....and I guess that's why it's a personal decision.
I would warn anyone to protect their health above everything else. Even if you aren't sure of a PA, if she has given a bomb drop.....then don't be bashful about reaching for a condom if she comes slithering across the bed in the middle of the night.
Turning away from that subject just a little bit, could you remind me if your W was molested as a child? (Sorry, my memory is slipping).
I may have already told you this, but I kind of suspect your W is involved with someone online (texting). She would view an affair online as "safe", where she can be whoever she wants to be in her fantasy......and, it can be at her own pace. Initially, she could even pass for a younger age, if she just sent a picture. (Eventually, he'd want to see live action). She might lie about a lot of things when talking about herself. As long as it is online, she doesn't feel the pressure of reality. She doesn't feel pressured to have physical sex with him, and they can just engage in other ways. She may lead him on, talking about how she's going to get her own place, yada, yada. To her, it's all part of the dreamy new life she's planning. She can even pretend she doesn't have to deal with her chronic health problems, and OM may have no idea anything is wrong with her. In the meantime, she gets all the benefits of being M to you. So, this could go on for a long time.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!
I will save you the time of hearing my 
