Speculation that the couple's marriage might be in trouble circulated after tabloids ran photos of Lachey surrounded by cheerleaders at a Super Bowl party in Jacksonville, Fla., and on reports that he dined with an ex-girlfriend.
"I trust Nick totally, and he trusts me," Simpson told Us Weekly.
Simpson, 24, says she didn't know Lachey had dinner with his ex-flame Jordana Jarjura, a meeting Simpson called "innocent." But the blonde entertainer, who stars with her husband in MTV's "Newlyweds: Nick & Jessica," says it was a learning experience.
"There are lessons to be learned," says Simpson. "Now Nick and I will tell each other about something like this ahead of time."