"I have a love in my life, a soul mate -- absolutely," Pitt said.
The Hollywood hunk told Parade magazine that he and brunette bombshell Angelina still have sparks between them after four years together -- and the couple often sneak off to the grotto behind a waterfall in the pool.
"It's a great place for sex," he said.
Still, the super star couple has no plans to tie the knot.
"When someone asked my why Angelina and I don't get married, I replied, 'Maybe we'll get married when it's legal for everyone else.' I stand by that, although I took a lot of flak for saying it -- hate mail from religious groups," he said.
"I believe everyone should have the same rights."
Pitt said having a family is more of a commitment than marriage. The pair has six kids -- all under the age of 10: Maddox, Pax, Zahara, Shiloh, Vivienne Marcheline and Knox.
"It's certainly more than the ball-and-chain that country songs sing about," Pitt said. "Our family is the base that gives Angie and me the long tether to go out and do all these other things. It's a big step we've taken. We've put down roots together. As Angie and I carve out our time as a couple, we carve out our lives as individuals."
Pitt also confessed that smoking pot turned him into an anti-social introvert as a youth in Hollywood.
"I liked to smoke a bit of grass at the time, and I became very sheltered. Then I got bored," he said. "I was turning into a damn doughnut, really."