hypochondriac

Hi everyone, this is my first post here and forgive me if it is a little long. I am in recovery myself and have been sober 10 years.
A year or two into my recovery I met my partner and he doesn't drink. He told me he used to smoke weed but stopped that too. Turns out that wasn't true. He carried on smoking weed (never much around me, even when we lived together) and he used to do the odd acid binge. He moved away for work and I found out after he left that he was attempting a geographical cure because he had been doing a lot of coke and wanted to get away from his dealer. I was naturally really angry about this because I had always been hoping he would give up drugs because he acknowledged they weren't good for him so to do something worse...
When he was working away he admitted to doing speed a few times but said no coke. Fast forward to this year and he goes into hospital with heart failure. Turns out during the pandemic when he couldn't work (and moaning about how bored he was all the time) he was doing A LOT of speed. He is out now and sweared he wasn't going to use drugs again. I tried to talk to him about options for support because I knew this would be hard for him but he doesn't acknowledge this.
I stayed with him for a few weeks and he seemed to be doing really well, then I went home for a week and came back and his flat stank of weed. He swears it wasn't him and a friend had smoked a joint in there but naturally I thought it was him because it was the smell was so strong. We have gone back and forth over the last few days and I think I do believe him now - normally he gets really dark circles under his eyes when he smokes weed and he doesn't now - but I am not sure if I am just being a mug.
Doc made it very clear that cannabis is bad for his heart. I have been doing a lot to help him and feel like a mug if he just lets me and just carries on doing drugs behind my back. I know the difference between acknowledging you have a problem and really accepting it from my own experience and want to give him the chance but it has been years of him lying about drugs and I really don't know if I should trust him. He offered to do a drug test which I may ask him to do - but not sure if I should just be trusting his word. I would appreciate any thoughts.
*For context everything else on our relationship is great and the drugs has always been a side issue which didn't come up much because he didn't really do them around me, but I know from my own experience how much addiction affects every part of your life.