Legal Question in Business Law in Arizona

Without seeing the actual lease agreement that you signed, I cannot give you a definitive answer. However, in general, when more than one person signs a lease, all the tenants are jointly and severally liable for the rent payments. That would mean that each of you is responsible for the entire rent due the landlord. It is then up to you or the ones actually paying the rent, to sue the others who are not paying their share. It sounds like you are using the premises for only a small fraction of the time the other person is using the premises, and perhaps you would have a claim against her for the greater share of the rent. But, be aware, you apparently agreed to pay 1/3 of the rent, even though your use was less than that.

You and the other person paying rent, should go after the 3rd person for his/her share of the rent. You must work out your deal with the other person, who is using the premises the most, as to what is owed by each of you.