Jeff Bridges says he would never jeopardise his marriage by cheating.
The Oscar-winning star is blissfully content with wife Susan Geston since they met in 1974 on the Rancho Deluxe set.
"I'm so in love with her - the relationship just keeps getting better and more intimate and sexier and all that stuff; you don't want to mess around with that," he told The Sun.
Jeff insisted the couple, who have three daughters, have got stronger over the years.
"If you change partners every time it gets tough or you get a little dissatisfied, then you don't get the richness that's available in a long-term relationship. My wife supports me and it makes me love her more," he added.
The Crazy Heart actor has worked with Tinseltown beauties including Michelle Pfeiffer, Kim Basinger and Jane Fonda, but said he won't get tempted.
"You don't want to get sexually involved with the other actor. It spells trouble. My family was and is too precious to me. I know sex can lose you everything," he said.