That isn't a relationship. That's fuc buddies, and your not even buddies. So you were two people who liked each other enough to have sex a lot.
Meth,will do that, totally screws the lines of reasonable behaviour and expectations.
I suspect if you stayed off it for a few weeks you would wonder what you were even doing talking to the douche.

Block him delete all numbers, and no keeping a contact "just in case" . He isn't a friend, or a mate, he is barely even an acquaintance, you just happen to work in bed. Terrible foundation for a relationship,especially because on uppers the thing's you'll put up with aren't what you would put up with normally.
(14years on amphetamines, so been there.)

Please please, just walk away luv . You KNOW he is screwing other people, that isn't gonna change anytime soon.

Pull yourself up and stop replying to his calls. He clicks his fingers and you go running?
Stop kidding yourself that what you have is something more than two people with an itch to scratch.

If you can accept that's all it is, then that's fine. Ignore all the other women, for god sake use protection, and stop expecting anything emotional from him.

If you want a relationship, go someplace else because he WON'T give you one.

Here wake up Hon.

All the best, and be kind to yourself.