Old band mate troubles?

How would you handle this?

I've been playing with a heavy metal/hard rock four piece for the past... uhhhh, I'm too lazy to count the years lol a LONG TIME. Before it, I was in a three piece acoustic duo that sucked. I never officially left the acoustic trio, and I play with them on occasion to help them shake the dust off. Both of them are in college and have jobs, so don't have a lot of time for music and I'm a musician full time. I learned, recently, that the lead guitarist from the trio has been rage-fully spreading horrible rumors about me and exploding in public places about what a horrible user and nasty person I am for dumping her and the other member of the trio... when I never actually did. I live in a huge city, but all the rumors that she started behind my back, have now found me (after several years of spreading them like "I can't believe its not butter...". She's been doing this and I never knew. Now she's damaging my current band's reputation by making me out to be a slut, poser, liar, cheater and blah blah blah... everything that I'm proud to say, I am not.

How would you handle this, as an adult? No "I'd beat the crap out of her", childishness. Adult to adult. I'm at a loss on what to do, because if I approach her, she'll explode and make me out to be a villain. Probably cry rape... (I'm a chick btw lol), but I'm not even joking. Its bad...

I've thought of just ignoring her. Trying to show her that she doesn't get to me. But she's not the type to just give something up. She'll keep doing it until one of us dies... and no, murder isn't an option, okay? O...o

BQ: is there anything worse than a pissed off punk rock diva???