You have legitimate concerns, as does your doctor. The problem is that there are no risk-free or perfect drugs for osteoporosis. I'd get a second opinion because, just maybe, there's a way to create a treatment plan that allows you to mitigate the risks by continuing a plan similar to what you've done already. That is, continue switching drugs to maintain any gains but dodge side effects before they kick in?

I'd also try to find a facility and doctor that use some of the newer technologies that look at a range of markets for bone health and focus solely on bone density as it's not the whole story. And you can do everything you can safely do to protect your bones, including reviewing your diet, adding supplements if there's a shortfall (calcium, vitamin D3, vitamin K2, trace minerals like boron, maybe collagen) and exercise that targets osteoporosis. Teri has posted about the online videos for Dr. Fishman's Yoga for Osteoporosis and others have posted other online sources of great information. So there are steps that you might be able to safely pursue in addition to getting some more answers.

I hope this helps. We're all facing the same limited choices to protect out little skeletal homes.