When enrolling in the Marketplace you should include everyone in your tax household including yourself, your spouse, and any people you expect to claim as a tax dependent for the year you want coverage.
If you are legally separated or divorced from your spouse, you do not have to include them as part of your household. If you are currently married but anticipate being divorced or legally separated during the year, you should file according to your current marital status and update your Get Covered Illinois application after the divorce or legal separation is finalized.