Secret Masturbation (Looking for outside opinions)

Back story: 3 year relationship. Started out as a work fwb deal. Great sex. Tons of passion. I even once was told by a coworker that my gf said she was "having the best sex of her life". 

Fast forward a year. Sex is sparse. Almost unhad. We live together. Blah blah. 

So one evening we're watching "House of Cards". I got up to smoke. When I came back in the room she shuffled. Being that I myself have widdled the magic wand in a crowded house I know that shuffle. As I sat back down I ran through all the thoughts brewing anew in my over-active brain. Was she just masturbating? Had she continued I would have gladly watched or took part myself. But she stopped. Acted as if nothing was going on. So, to test myself and clear up the oddity I had obviously created in my mind... I got up. I went to the kitchen. And I waited a minute. I poked my head around the corner and to my surprise, there she was... Widdling away. She came as I stood watching in sadness. I crave her sexual attention. And this is what I get. I confronted her. She denied but I saw it. There was no denying it. So she came clean (dirty bitch 😈). She said "I had to. I can't explain it!" 

It was weird for a bit but we moved on...

Fast forward 2 years...

Still in a near Sexless relationship. I say "near" in the hopes that I believe it. But here is my new situation. We were in bed a few weeks ago. I felt the bed shaking. Not in an earthquake kind of way. More like a trembling shake. Like if you were trying to keep quiet while jerking off. Or if you were viciously rubbing your clit. If you know you know... Anyways. I brought it up the next morning. Denied. Ok. Maybe I was wrong. Few days goes by. It happens again. I mention it in a more carefree kind of way. Denied. Then I started paying attention. When I thought she was in the act, I thought I felt her toy touch my hand and I reached for it. She abruptly yelled at me to stop moving. She was trying to sleep. I stayed quiet. The tremble started and I tried to touch her pussy. She turned. I accused on the spot. Arguing ensued. She swears she wouldn't do that. (I recall that "one time") she assures that I'm crazy. 

Next night. She gives me this very child like explanation of how she sleeps. "My hands are up here. I'm on my side. I couldn't be touching myself. I'd need to be on my back." To me this was a very "look over here" kind of a distraction. Also her tone made it seem as if she was trying to undermine my thoughts. Talking to me like a child to insinuate that my accusation was immature. But it made my brain start turning. How could she be getting off if her hands were clearly not in her pants. Then I remembered. We bought her an anal plug that she had previously stuck in her pussy and walked with inside of her for hours at work one day. She had to remove it because she came just from walking around. So the next night with that in mind the same events took place. Tremble........... Small unrecognizable sound/exhale.... Stillness. And like clockwork within seconds... Snoring. No different than if we'd have had sex minus a clean up. Denied. Denied. Denied. Next day I went looking for the plug. I knew where it had been. She had even shown it to me and said "am I supposed to be using this thing?! Ha!" Again, my accusation dismissed as pure stupidity. I couldn't find it. She couldn't find it. After I smirked and said something about "life's a mystery" I rolled over and closed my eyes while I could hear her searching the room. Looking in all the places I had looked. And then she says "it's right here. It was in the drawer." No... No it was not. Absolutely nothing was in that drawer. At this point she shoved it into my nose. I myself felt that went a bit too far physically but I let it go. She the proceeded to throw away all of her sex toys. We had to agree to disagree. She says it never happened. I say I can pinpoint where at in the process she is all the way to predicting the snoring within seconds of it starting. But agree to disagree. 

I've come to the understanding with myself that she has an issue with Masturbation. She feels embarrassed or shameful. Whether or not that is entirely based on my initial reaction or it goes deeper I do not know. But if she "has to" and she just can't talk to me about it... Sobeit. 

If she was just open about it I would be cool. I'm OK with her rubbing it out. Idc if I'm right there. Prior knowledge would be cool. Or an open invitation to take part myself. In a solo manner. But knowing how much I want her. How badly I desire her. It's almost cruel. 

It happened again tonight. Tremble. Unaudible sound... 3, 2, 1... Snore. I didn't get mad this time. I just sighed at my life. Got up and came to spew my thoughts in my journal. Then I found this. I hope I get someone's thoughts. I'm out of good ones.