Once something is defined as derogatory, it is forbidden to relate it other than for constructive purposes and under specific conditions which will be discussed later. One may not share negative information about people with friends and family including one’s spouse. It must be underscored that relating loshon hara to ones spouse is no less forbidden than when relating it to anyone else. To focus on another’s shortcomings is undignified and wrong.
Sefer Chofetz Chaim, 16 Tishrei, page 80