My husband's friend let us use their studio and I don't want to pay them.
That doesn't seem right, why don't you want to pay him?
The payment isn't fair. My husband is the one doing the recording, but I'm given the bill.
Your husband can help you pay it back, can he not? It sounds like he was using the studio recording time, which means that the two of you should have to pay. You owe him, and not giving him the money that you owe is a very poor thing to do to someone.
I will pay him back and never have any money problems again.
Paying your debts is the right thing to do and even if it was your husband who used the studio, it's a debt you share as you're married. You'll feel better once it's paid and settled.