good morning. you said your boyfriend says its very difficult to avoid cocaine, well he is right. it dosen't sound like he wants to quit. using cocaine does cause extremely erratic behaviour and when i used i was up and down like a yo0yo. it seemed when i was coming down from coke, i was so angry and irritable, i screamed at anyone trying to talk to me sometimes.
im just being honest here so don't take offence, but as long as he keeps using, it will be hard to improve your relationship, because cocaine may become him main priority, more important than family friends, and himself. can you sit down and talk to him. is there a chance he wants to quit. i really don't think you can make him quit, he has to want it for himself. most times someone using coke, uses a lot more than they let on.
the best way to improve your relationship is to help him get off this deadly drug, and no matter what, please don't ever try it, it is the devil, trust me