Holly Willoughby says marriage is something that has to be worked at.
The 'This Morning' presenter - who has been happily married to television producer Daniel Baldwin for nearly a decade - believes the secret to wedded bliss is not underestimating the effect "tiredness" can have on a relationship.
She said: "Marriage is something we have to work at. You're an idiot if you think you just get married and then you tick along happily ever after for the rest of your life. At the same time it shouldn't be too difficult, but I do believe tiredness has a lot to answer for. Everyone underestimates the effect it has on you as a couple.
"Whenever I see people breaking up shortly after they've had a baby, sometimes I wonder if they'd just given it a little bit longer or pushed through that tough bit at the beginning ... Not that I profess to know everything about other people's relationships, but I think that people may make decisions at that stage and then wish that they'd just held out or worked through it."
And Holly - who has four-year-old daughter Belle and sons Harry, six and Chester, 18 months - urged mothers to "give themselves a break" and try not to put too much pressure on themselves.
She added to The Sun's Fabulous magazine: "I think as a woman, when you've just had a baby your hormones are raging, and they make you see things differently. They make you feel different, your body looks completely different, and you might feel completely unsexy.
"You're not going to change any of that, but I think just give yourself a break and say: 'I'm not going to make any decisions, I'm not going to put myself under any pressure to look a certain way, be a certain way, behave a certain way. I'm just going to ride this because I know that motherhood is going to be brilliant and crazy and terrifying all rolled into one.'"