Buy a tongue scraper. Bad breath can have a lot of causes; the foods, gum disease, infections, failing dental restorations, sores in the mouth and respiratory infections. However, 90% of the time bad breath is the result of a dirty tongue; gases produced by bacteria in at the back of the tongue. About 1% of bad breath is caused by systemic disease.
Boyfriend bad breath. If brushing his teeth and flossing does not eliminate the bad breath, have him brush his tongue. Also check his diet. Certain foods like onion and garlic can cause foul breath. If this does not help, then he may have tooth decay and/or gum disease, and needs to see a dentist. The bad breath may also come from a systemic disease, in which case he will need to see a physician.