You need to have 2 separate businesses, and each business will be on a separate schedule C. If you are in the "self" schedule C, only enter expenses and income for self. You must exit the self schedule C and enter the spouse schedule C to enter spouse's income and expenses. If you need to go back and change or add something to the self business, you have to exit the spouse business and re-open the self business.
Gig work is rarely joint, unless you have specifically formed a partnership where you are running one business with more than one person contributing. And if that's the case, you need to file a business return for the partnership (form 1120) BEFORE you file your personal tax returns. Partnership returns were due March 15, not April 15, and if you didn't get a specific extension for the Partnership return, the late fees are $200 per month per partner. Partnership returns have other complications (like the need for a special tax number). You don't want to go down that road unless you have professional tax help.
