The Rolling Stones' outrageous frontman and hard-living guitarist told the Times newspaper on Friday that too much is vested in their love-hate relationship to let it fall apart.
"I don't know if it's some sort of inner competition, maybe that's the chemistry that keeps us going," Richards was quoted as saying.
"The fact is we're totally different people, but we're attracted to each other at the same time, and there's also the recognition that we can't get divorced."
Jagger and Richards first met more than 50 years ago as young schoolboys, but it wasn't until they were students at the London School of Economics that their friendship blossomed.
In 1962 they founded the Rolling Stones, and amid the drugs, women, money and worldwide success, cultivated a volatile relationship that frequently threatened to fall apart.
Richards has publicly ridiculed Jagger's ego and poorly received solo musical efforts. Earlier this month, he sneered at the singer's recent knighthood, calling it a "paltry honor."
"He's got a big mouth," Jagger told the Times. "He likes to make out he's still a very rebellious 59-year-old. That's all right, that's the role you play.
"We have a pretty good working relationship. If he needs covering, I'll cover for him and if he needs to cover for me, he will."
As the Stones prepare to launch their first world tour in three years, which begins in Boston this week, the pair reject criticism they are a quartet of wrinkly rockers who don't know when to exchange the stage for the rocking chair.
"I think we just want to see how far it can go," Richards said. "There's a great feeling in the band that we ain't really found all that the Rolling Stones can do yet."