We started an LLC 8 years ago. When I looked it up I thought that a husband and wife LLC could file as a passthrough entity. Now I found I was wrong. How do I fix this?

I found out because we did a 1031 exchange and had to fill out the W9 as a partnership. I argued with the 1031 company and realized my mistake. We have never filed under the LLC but have paid all the taxes under our joint tax return.