I was on C for 4 years and DID have flare ups while on it. In the end I simply couldnt take it anymore, as it made me feel miserable.

DMDs cause you to have FEWER relapses, and fewer lesions to come on, but it wont prevent them all. It will just make them less severe.

Its a tricky spot to be in. I hope you are able to talk WITH your MD instead of having him talk at you. I hate when they do that.