Yeah, you really do need to. If you ever want to be someone she truly respects, not someone she treats as a disposable safety net, she needs to see that what she's doing is not ok and that you have your limits. What's the use of her coming back to you if she just dumps you and pretends to the world to never have loved you AGAIN the next time a guy says he'll take her out some time? Sorry to be harsh, I feel for you. :/
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.