Yes you can give the virus to other people without knowing. Its called viral shedding.
You aren't getting reinfected...you ARE infected with the virus. It stays in your spine for the rest of your life. It will always be there. Your body and/or anything else cannot kill it. You can treat it...but thats it. Several factors lead to an outbreak (what you were saying as being "infected"). These factors include not getting proper sleep, not eating healthy, smoking, and stress. Stress is the biggest cause of outbreaks as herpes virus stays at the base of your spine and travels via your nerve cells to your skin when its very active.
Viruses are opportunistic. They take advantage when your body is weakest. So basically if you are living unhealthy it will make it easier for you to get reoccurent herpes outbreaks.