Secretive alcoholic partner?

I have reasons to believe my partner is a secretive, functioning alcoholic. We have been together for five year and have two children together. We are in our 30s. When we first got together I was aware he was addicted to weed. He would get stoned each night. I stood by him even though I hated him smoking it and supported him when he wanted to quit. It's been over two years since he has last touched weed. He then quit smoking cigarettes and turned to vaping. He then set up a man cave down stairs and spends an increasingly amount of time down in his cave. Our relationship struggled mostly due to be getting annoyed by the now non existent affection and intimacy. His life was all about vaping and his vaping fb groups. One night I caught him watching porn. I was deverstated that he choose that over me. This had gone on for 6 months. Things appeared to be improving between us. Until I noticed personality changes in him. He often had blood shot eyes. Was also drinking a lot of Pepsi
He never drank softdrink. I thought nothing of it until I went into his man cave to grab some batteries and noticed 50+ empty bottles of whisky. He never drunk alcohol. It's one of the things I admired most about it. As I also don't drink. My father was a alcoholic. Lately I have seen him hiding a bottle if whiskey in his man cave. A day later it's empty. Along with the Pepsi cans. His personality changes. His more playful and a bit rough. His also much more intimate. But he says somethings that scare me. Like how he would kill me. What he would use. His even gone as far as looking up how to do it in front of me. I'm getting quite bruised by his over playful ways. I've never seen him actually drink the alcohol. So would be doing it secretly. He was also diagnosed as having Aspergers. If that is relevant. I refuse to be with a alcoholic. He denies it. I have no actual proof. Only what I have seen by the empty bottles and his behaviour change. What to do I do? I'm scared and angry.