Im having difficulties understanding what is the purpose of a one to one relationship

I have a form where users fill out the information, and select a benefit type.

For example, I have a model of 

```
class BenefitRequest(models.Model):
    benefitType = models.OneToOneField(BenefitType)
    description = models.CharField(max_length=100)
    benefitAccount = models.ForeignKey(BenefitsAccount

class BenefitType(models.Model):
    benefit = models.CharField(max_length=25)

```

In my database, for the BenefitType, I have Commute, Fitness, and Ergonomics

However, when I fill out the form and select "Fitness" for PersonA and submit the form, then select "Fitness" again for PersonB and submit it again, it gives me an error stating my BenefitType is already used. Even though it is a new request for another user.

Does that mean in django, a one to one relationship is where a table can have only 1 type of each of another table?