My ex was badly addicted to coke by the time I realised he was more than just an occasional user peer pressured into it. We were really young and didn't live together so my experience might be different.
The first sign was the hyperactivity, running off during nights out (actually running - he and his friend had started to do this under the guise of something cool and random to do, it stopped any questions) and staying up for full nights at a time. He was a musician and started staying up all night writing songs and playing his guitar, so when I stayed over that's what he'd do.
After this came the issues with sex, unable to last longer than a few minutes when previously he had no issues, then he had occasions of being unable to maintain an erection. He convinced me that it was because he was nervous, that he'd put himself under a lot of pressure to make it better for me. Another lie.
We went for a weekend away, he spent the whole time feeling weak and ill. Then he couldn't urinate, on the last day he had to lie down after we'd packed our things, he was sweating, clearly agitated and struggling. He told me he had a water infection and had forgotten to bring his antibiotics.
He then started to have money issues, the time I realised it was a big issue was when he said he had an appointment with the bank. He said he needed £500 and if he could deposit that amount into his bank the next day he'd be given a better bank account with a free overdraft facility, this would then help him to get out of debt. He made me drive to the cash machine late at night (and desperate for me to do this before midnight) to withdraw £250 (max amount allowed). He then forced me to drive back there after midnight for the rest!
The next day when I woke up (staying at my house) he'd left me a note to say he couldn't sleep so he was going home. I actually fell for that one too.
He started having nosebleeds, then a lot of anxiety and eventually panic attacks. He'd spend whole days in bed too scared to get up. When that wore off he started to have chest pains and even went so far as having medical investigations as to why. I don't know what the outcome of that was, he never said.
Eventually this all came to a head when he flit in the middle of the night and left the country. He confessed over the phone and I ended up having to bail him out with a lot of money. He returned once his debt had been paid off, I did that for him on the agreement that he wouldn't contact me again.
Of course he tried but by this point I'd wised up a bit. The suspicious behaviour was quite subtle to start with and built up, which is most likely why I didn't notice it.
Honestly, OP - leave, don't look back. Once someone has gone down this route it will always be their priority. And if sourcing and taking it isn't a priority then trying to avoid temptation will be. You deserve better.