If you and your husband had and were using separate user accounts, you might first begin by deleting his user account. This would erase his home folder and all of the documents and data that are in it. You might be surprised how much space you can recover just by doing that.
Log into your own account and, assuming that it has admin privileges, go to System Preferences > Users & Groups, unlock the panel, click his account and then the "–" button at the lower left. Follow the prompts to erase that account.
Please see: Delete a user or group on Mac - Apple Support
Afterward, you can evaluate the storage remaining on the startup drive and proceed from there as you like.
Much easier than erasing and reinstalling the OS, etc.