What if your spouse refuses to pay taxes on earned income?

I suggest not filing a joint return. Using the Married Filing Separately filing status will not allow you to claim some tax benefits and you won't have the benefits of combining your income, but it will save you if your spouse is audited. If you file jointly, you will be fully responsible for the taxes on the omitted income. Filing a joint return creates something called "joint & several liability" which means you are both responsible for the entire tax liability, even if it's later adjusted because one spouse omitted income or committed tax evasion. Read IRS Publication 971 to find out the difficulty of not being held responsible for your spouse's actions. That's why I recommend not filing a joint return with your spouse. The benefits will not be worth the cost if they are caught evading taxes.