So, you have proof that she was taking the first steps in cheating on you yet again and rather than be apologetic or remorseful she gives YOU an ultimatum? No. It sucks to think about tossing out two years together, but that is ridiculous.
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.