Sorry to hear about this, Jenn. I know its not easy to be objective when it comes to family. I'm glad you talked to your MiL and cleared that end up. =]

I, personally, would think about the hidden why your sister is doing it. Is she trying to get attention? Trying to get a reaction out of you? If so, why? Not that you can be positive, but usually there are subtle signs that look ordinary until you see them all together. I have a sister that is almost exactly like that. She snorts hydrocodone (which she gets by rx) and cocaine, does meth sometimes, drinks when she can. She has 2 kids, oldest is 3.5years old, younger is 1.5years old. She hasn't gone to the extreme of telling outrageous lies, yet. She used to steal from my mom alot, but since we moved in it hasn't been happening. She will thief just to do it, inconsequential things. She has my aunt always on her side, was always her favorite growing up, and my aunt gives her money, cars, pills, weed--pretty much whatever. /My/ sister just tells small lies that are easy to get away with--that if you check with the other person and mention what was said, they will usually pass it off as misunderstanding. I think my sister's is mostly a dumb power trip type thing...she does it to see if she can get away with it. She WAY over reacts when caught, stomps around, yelling, slamming doors--that kind of thing. Throwing a tantrum because she didn't get away with it, basically. So the small crap I don't worry about, she hasn't tried anything with me on a large scale yet.

Not trying to get off track, here, but have used my sister's behaviors to illustrate a way to look at. Question it--Why? Maybe she is jealous of how independant you are, or of your relationship with your husband. I have no idea if those are relevant to you or your sister, but you see what I am getting at, I hope. I don't know, that's just how I do things...and I know I'm a veryyyy small minority in most instances in regards to behavior, so if its too weird, disregard. -shrugs- I won't mind, I know I'm weird