In my experience I wouldn't tell him.. chances are he already knows about her drug use.. and another thing to think about is.. blood is thicker then water.. in my situation, my ex's parents were well aware of my ex husband drug issues but they also were in denial about his problem and when I told them they seemed to appreciate my concern but then they turned around and threw me under the bus.. it didn't matter because I was divorcing him anyway.. but that's just it.. she's your ex, she's no longer your problem.. keep it that way
