Is it okay to share toothbrushes with my significant other?

No!! Sharing toothbrushes means sharing germs.... germs that may differ from the normal bacterial makeup of your mouth. Keep in mind, periodontal disease is named that way for a reason! It's an infectious disease that can be transferred from one person to another, and can manifest itself without good self care and regular check-up visits to the dentist! Thus, it's always important to have your own toothbrush.