Addiction

MY husband was is a crack addict for the last 6 years. When i met him, he was so called clean for 2 years. Well to my surprise he had his often relapses. I found out when he did a disappearing act for the whole night and threatened to leave him. He swears he has now stopped. I am very naive and dont know what to look for. He smokes marjuana which I dont like but accept. The use of marjuana is declining as well. How do I know if he is still on crack/coce? He does not disappear anymore, but he works with guys that use all kinds off drugs. Please give me advice,.
I didn't know when my boyfriend was using at first either or what signs to look for. But after time, now he can't get away with it even if he just phones me. How I can tell is his voice changes. Usually he's hyper, but when he's on crack, he sounds "depressed".
Also he gets these white stuff at the corners of his mouth. His heart rate is up and they have this sweet chemical smell coming out of their body.
Also they sweat A LOT.
He loses interest in stuff that he usually likes and wants to be away from me, like going to the car wash which takes 45 minutes and being late with phone calls. Also their appearance declines as well. Look for those signs.