"filing his return under his business"
Your husband has to file a personal tax return. That should be a joint return with you. If his business is a sole proprietorship or a single-member LLC he will include the business on Schedule C in your joint personal tax return. If his business is a multi-member LLC, partnership, S corp, or C corp, the business has to file a separate business tax return, but your husband still has to file a personal tax return. The business tax return does not replace his personal tax return.
