Goldie Hawn is "constantly working" on her relationship with Kurt Russell.
The 70-year-old actress admits the pair - who have been together for 32 years - go through their "ups and downs" like anyone else.
She said: "We have our ups and downs like everybody else. You have to want to stay together, and we really want to. Therefore you work to be together."
The 'First Wives Club' actress is teaching children about happiness as part of her MindUP program, which is part of The Hawn Foundation but insists her life isn't always "happy".
She told PEOPLE magazine: "The ups and downs of life are there. It is not always happy.
"What we want to help children with is, just because you feel sad or happy or depressed doesn't mean that is who you are. We want them to know, 'I am really sad right now but I am not a sad person.'
"I always wanted to understand the causes of happiness. I'm a bit of a scientist I guess you could say."
Meanwhile, Goldie doesn't feel the need to marry her long-time partner Kurt because "compatibility and communication" is far more important than a piece of paper.
She previously said: "A lasting relationship isn't about marriage. It's about compatibility and communication.
"Intention is the key. It's also about not losing yourself in each other. Being together, two pillars holding up the house and the roof, and being different, not having to agree on everything, learning how to deal with not agreeing."