Hello nica, welcome to the forum.
May I kindly suggest you review this forum thread called
All New Guide - How to apply for a Fiance Visa
You'll notice that solely in terms of the Financial Requirement it's only dependent upon the gross annual income of your fiance. UKBA are not all interested in the outgoings or balances of his bank statements. The only interest in the bank statement is to confirm that the stated salary is being deposited there by the employer.
Hope that link will help you to understand the visa requirements