The couple, who were married in 1995, divorced in 1998. They have been on and off again ever since. They were photographed together in Hawaii last month, and that's when the marriage rumors started, Lee said.
"I took Pamela and the kids to Hawaii for her birthday. And anytime we get together for any length of time, people are like, 'Oh, they're getting married,'" he said.
Anderson had told reporters she and Lee weren't getting back together, but the 42-year-old rocker renewed speculation when he told People magazine: "We're crazy in love. We're going to take things slowly and see where they go."
"You know, we're stuck together forever. We love each other dearly and we have two beautiful kids," Lee told Leno. "But as far as getting married or engaged, I'm not engaged or married."
The couple have two sons, Brandon, 9, and Dylan, 7.
Lee's new show, "Tommy Lee Goes to College," (search) debuts Aug. 16 on NBC.