Could you stay with someone from 13-18+?

Could you stay with one person throughout your entire teen life? I know some people who have been with the same person since they were 13 years old and now they are 16, 17, and 18 years old and still with the same person. I just find it rather odd I guess, since I have a new girlfriend every month, but still, I mean, staying with one person for that long, that's quite a commitment. Could you ever stay with someone from the age of 13 through all of high school or even the rest of your life?