The Colorado Family Purpose Doctrine
The general rule is that liability for a debt rests with the person who incurred the debt. However, like most general rules, there are many exceptions. One of those exceptions is something called the family purpose doctrine.
The family purpose doctrine states that the expenses of the family and the education of the children are chargeable upon the property of both husband and wife, or either of them, and in relation thereto they may be sued jointly or separately. In simple English, this means that both husband and wife are responsible for the grocery bill regardless of who went to the store.