updated 01/06/2014 AT 5:00 PM ET
•originally published 01/07/2014 AT 10:00 AM ET
“I’ve learned that sometimes love is not enough,” Simpson, 33, tells Redbook in its February issue, on newsstands Jan. 14. “You can have a soul mate and be madly in love with that person, but it’s not necessarily enough.”
So what is the secret to a long-lasting relationship?
“I think you have to have personalities that mesh well. You have to be the yin to their yang. You also have to be open to figuring things out together and communicating even when it’s the last thing you want to do,” adds Simpson, who divorced first husband Nick Lachey in 2006.
“I have to admit, it doesn’t hurt that Eric is one of the hottest men I’ve ever seen and he looks amazing naked!” she jokes.
But on a much more serious note, Simpson told the magazine that a downside to her pregnancies with the couple’s children – son Ace Knute, 6 months, and daughter Maxwell Drew, 18 months, was the media scrutiny over her weight.