Living under the same roof with someone is a phrase that describes sharing a home with someone. It implies living in a close relationship, such as husband and wife. This phrase is often used when two or more people are living together in the same house. For example, a woman may be disappointed that she and her best friend don't live under the same roof.
Cats and dogs may not be natural enemies, but they aren't natural friends either. When they live together in the same house, they can compete for food, water, territory, and attention from people. If the two animals live together for a few years, they can come to an understanding and learn to respect each other's needs. The phrase "under the same roof" is often used to emphasize that two or more people are living together in the same house.
Many families today don't fit into the traditional mold of a husband, wife, three children, and a dog all living under the same roof. It can also be used to describe other situations where two or more people are living together in the same house. For instance, someone might say that as long as their pet dog Felix was living under the same roof as them, their partner wouldn't have to bother them so much about it.