Talk to your boyfriend about his hygiene. Sit down together in a place where you are both comfortable and turn off distractions like the television or radio. Discuss your concerns, but don't tease him about his hygiene or make rude comments. Point out aspects that you enjoy about your boyfriend then mention what bothers you. For example, if he has an untidy beard, tell him that although you enjoy kissing him, it scratches your face and that he would be equally as charming without it.
Go grocery shopping with your boyfriend. When you're in the hygiene section, pick up the supplies you normally use in your routine. Tell your significant other that you noticed he's running low on items like toothpaste and soap and add them to your grocery cart. You can also shop by yourself and take hygiene products to your boyfriend. For example, if you want him to wash his hair more often, purchase a new shampoo and conditioner and let him know that you fell in love with the scent.
Spend one day a week doing laundry together. Clothes should not be worn multiple times, so encourage him to avoid reusing dirty clothes. Help him keep track of his dirty laundry by getting him a hamper for soiled clothing. Dedicate a portion of laundry day to helping him clean his home.
Provide your boyfriend with hygiene reminders. Keep a bottle of sanitizer or antibacterial soap at the kitchen and bathroom sinks so he can remember to wash his hands before handling food and after he uses the restroom. Explain as you excuse yourself to visit the restroom before leaving a restaurant that you must floss -- but not in public. Offer your boyfriend a floss pick. Upon leaving the restaurant, provide him with a mint or stick of gum.