Jaynielou,
If I were you I would get out now. From what you’re saying it sounds like you’re already trying to take control of his finances to help him get clean, and despite that he’s still throwing it back in your face and buying drugs at the first opportunity. He doesn’t admit he has a problem so there’s nothing anyone can really do for him until he does. You need to protect yourself and your own well-being.
You’ve only been with him such a short time for all this misery. It isn’t worth it. He needs to change himself and you need to look after you. I’ve been with an addict a lot longer and he’s now relapsed time after time in the last year, and because we’ve bought a house together in that time I’m somewhat trapped. If I were you, I would run and never look back.
Wishing you all the best x