Diff, might be time you start separating accounts and changing logins. You shouldn't be reading her emails and she shouldn't have access to your skype, its just going to keep hurting you. You seen how it effected you after you read more about OW. You became disgusted with W and has a backslide shortly after.
You can see some instances of how W still has feelings for you through her actions. Physical Touch and reading your conversations, yet she doesn't care for you anymore? BS, shes still in there somewhere. We just don't know if they will ever come out.
Unfortunately those feelings are buried under the chit that OW is providing her, they cant escape until OW is gone. OW will be gone, you have seen issues with that already. Its only a matter of time before it self destructs as almost every other A does. The more you read that email the more it will corrupt your mind against W, which will hurt you later on.
Also, this may or may not be true but she may know you can read that shared email and is planting those emails to mess with your head, catch you off guard and make you react. Much easier for her to keep doing this when your resisting and being that enemy. Its still likely shes just so far in the fog she doesn't think about it, but you never know.
At the very minimum you need to lock up your own accounts so she cant see what you're doing. Think about how much ammo this site would give her and OW to talk chit about you, even bond more against what they see as the common enemy. Leave them to their chaos so W can realize who the true enemy was(OW).
Accept what is, let go of what was, and have faith in what will be