I'm struggling to recover from bulimia, how to keep relapsing?

Stay in treatment: Consult with a Psychiatrist who is familiar with eating disorders, and get a thorough evaluation. While there are not specific medications that always work in bulimia, in my practice, with my patients, I have found that some combination of medications with psychotherapy help tremendously.

To reduce the damage to your teeth you may want to consider the use of protective clear trays filled with a baking soda “retainer gel”. The act of doing this may help you change your habit and at bare minimum reduce the thousands of dollars of harm to your smile. Better to prevent it than repair it later:

Certainly you should consult with a Psychiatrist first. Multi-modal treatment including Psychotherapy, medications like Prozac, counseling, Nutrition education, etc are essential components of management.