After a year of problems with my SS18 I have had it. I came home yesterday and went into his room to grab something and a bong was sitting on his bedroom floor in clear view. I have let a lot slide to keep the peace in my house but that was the last straw. I had a long talk with DH last night and we have concluded a list of expectations/house rules - I typed up a "contract" that all three us will sign and if he doesn't follow the rules he needs to move out. I hope this works because I cannot continue living like this.