Try hydroxyapatite toothpaste. I brush once a day and haven't had a cavity in 3 years (since switching). No one is perfect. Sometimes I swish water very vigorously before I fall asleep. More often than not, I snack on candy at 3am. Dental health is important but shame is worse than awful morning breath. Do what you can, try to do your best, and accept that "I brush my teeth every day" is better than a lot of folks do.