chocolatelover,
No apologies necessary, your "epiphany moment" was helpful to read. And Mr. Unstable made his point very well.
Just as an update, the breakup occured two nights ago. It took me that long to gain the strength and courage. There were other issues besides the marijuana use and it became so overwhelming that I couldn't take it anymore.
I'm at peace with my decision right now, and hope it stays that way. I've been known to get lonely and scared and fall back into a bad relationship, but I'm hopeful this time will be different. I'm lucky enough to have many supportive people in my life right now, including some of you who have responded to my post.
Thank you for your input!