I wouldn't worry about telling him, because it's not going to do any good..he will deny, come up with an excuse, and turn things around on you...try to make YOU the bad guy.
You did it, you found out what you wanted to know, so let it go.
Try to put the focus back on YOU and stop worrying so much about what HE is doing, what HE is going to think about this or that. HE is using...I can TELL you what he's thinking....using more. That's what we A's do. Until he hits bottom, it's going to get worse. As long as he can keep stringing you along, he will drag you down with him.
Please focus on you...he's doing what he wants.
Hugs and prayers!
Amy