The 70-year-old actress discussed her reluctance to wed the 65-year-old actor while appearing on Monday's episode of the ITV talk show Loose Women.
"[We] would have been long divorced if [we'd] been married," Hawn declared. "Marriage is an interesting, psychological thing. If you need to feel bound to someone, then it's important to be married. If you have independence ... there's something psychological about not being married."
"For me, I chose to stay, [and] Kurt chose to stay, [unmarried]. And we liked the choice," she added "After all these years, you think, 'Why [would we]? It's not working? What is marriage gonna do? What does it promise you?'"
Hawn and Russell, who have been together since 1983 and share 30-year-old Wyatt, were both married prior to their relationship. The actress is also mom to Oliver and Kate Hudson, while Russell is dad to Boston Russell.
"A lasting relationship isn't about marriage," Hawn previously told Porter magazine. "It's about compatibility and communication. And you both need to want it to work. If one person does not want it to work, it isn't going to work."
"It's also about not losing yourself in each other," she added. "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. Everything's a choice."