Not enough?

So ill try to keep this brief the wife and I have been together 4 yrs at the beginning our relationship was hot and heavy intamicies 5-6 times a week or more as with all relationships that has dwindled but to an alarming rate 2-3 times a month if im lucky. Now my wife has always been a bit prudish very vanilla if you know what I mean she refuses any kind of oral stimulation or anything risqué. Even though due to her oversharing about her past i know she has not denied these things to previous partners. So with our lack of intimacy I've naturally turned to porn I've tried to involve her with that as well and have been shot down to the point of her threatening to leave me because I am " a disgusting sex addict and porn if absolutely disgusting and it makes her sick" now a good few months back someone told me some not so good things about my wife I love my wife more than the world and I would not believe these things without proof but I'm also a person with deep rooted trust issues so I took the investigation upon my self. I installed a keylogger in her phone and a nanny cam in our bedroom. As I suspected the allegations of adultery are yet unfounded however I have discovered that she despite denying me and fighting with me frequently masterbates to girl on girl scissor porn. So why does she deny me and vilify me for porn or anything apart from traditional missionary sex but do this behind my back? Why am I not good enough? I don't know what to do anymore I don't want to call her out and risk my relationship but I can't feel this way forever and I can't bottle the feelings of unworthiness up its eating away inside....HELP!!!!!