Hi there,
First of all, I am so sorry you are going through this. I dont know if this will make you feel any better, but I know exactly what you are going through and feeling atm.
To answer your question, I cope by doing my own stuff, watch series or hangout with friends. Because worrying about him using won’t make the situation any better. Sometimes when he does use or like the morning/night of it he will text me stuff and I just know by the way he text he’s on drugs, I always asked him if he’s on coke and he would always say yes, whenever he says yes I always thank him for being honest with me because most of the time when he doesn’t wanna admit to me is because of the shame and guilt he feels. So that’s why I thank him and show him that its okay to admit to me whenever he’s using (also so he sees that Im a safe space for him)
I also feel frustrated and hurt by it, believe me but one thing, I never ever can get mad at him because I know its not his intention to ever frustrate or hurt me, same goes for you! I think you are arguing with him all the time because you turnt your frustration and hurt into your coping mechanism, I also had that for a bit but I just realised it’s not worth the fighting and saying things to him that you don’t actually mean, it only causes damage. Ofcourse what you feel is very very valid dont get me wrong, but whenever he uses try to vent to maybe a close friend? Someone you trust, or even on here to me. I found out, if I vent it all out it creates more space in my heart and brain to think more clearer and let the emotions out.
I am all ears. x