Think my heroine boyfiends cheating?

Okay my boyfriend is a heronine addict he slams I know not the perfect guy but that's my business .... he has been distant he comes hOme and goes to the bathroom runs the water for days and I walked in and it smelled the body wash I use ?? He told me he was washing out the needal supposedly but his pants were sagging like he had them down then when I confronted him he couldn't remember and it was like 3 hrs later then he has been deleting texts but it's because he doesn't want me seeing him calling and asking people for hi drug I really think somethings up and I want to know how do I find out??? I feel hopeless