Husband on drugs

So I've been married for 3 months. I kept finding straws in his Jean's I always asked him why he had them he said he would bite on straws because of his anxiety didn't believe it but I didn't want to accuse him of anything at that point until I actually seen the drugs .so days go on and one day he fell asleep when I got off work I found a baggy with white substance I confronted him about it he said it was his friends .I knew it wasnt his friends so i lied to him that day that his mom wasnt feeling good and took him there so we could all talk to him about it. He admitted to it and said he would stop. I told him I was done to grab his shit and leave I told him before we married I was not going to tolerate something like that. So we get home he begs me not to leave him .that he doesn't want to lose me and bla bla bla. He told me I'll cut my friends off,drug test me,and if you find any evidence you can leave me. Ok we talked it out and my question is I'm I doing to much by drug testing him when ever I suspect something?