Do I stay or do I go?

I've been in my current relationship for about 3 years. I have a history of being in really toxic relationships, including domestic violence and people who struggled with addictions. This is the first relationship I've had with someone who is kind and loving and affectionate. He's bought me flowers almost every single week since we've been living together (about 2 years). He cleans and helps out with household chores. He works hard, supports me in my dreams. The sex is really good. It's been almost a dream relationship until I started seeing signs of him smoking weed. He has a history of addiction with weed, like all day every day. He admitted and was open about this while dating and said he was clean for years. The next door neighbor offered him some over the fence and I guess it started up again. For six months, I was smelling it and finding lighters all over the house. I found papers in his pocket while doing the laundry. Every time I confronted him, he lied to my face, even going as far as to tell me I'm crazy. Until finally I went through his stuff and found the weed and he could no longer lie anymore. Thing is I don't care if he smokes weed if it's in moderation and can be controlled. My problem is his history and I've been watching it get out of control to the point that it seems like he's always high and he just feels unavailable. It doesn't affect his work or going to school, as far as I know. And I told him we could work through this is he could learn to be open and honest about it. But he refuses to tell me how much he smokes and how much money he spends on it or even where he gets it. I went through his phone (bad I know) but I found out he's even gotten in contact with old weed friends who are female. And now I don't trust him even more and feel like he's going to cheat on me. At this point is it worth my energy and effort trying to get him help or at what point should I throw in the towel? I've asked him to leave but I'm having a really hard time enforcing it because with Covid I have lost all human interaction with other people and I rely on his help paying the rent and I'm scared of losing my house. There's so much that he does right that it's hard to lose him.