Robin Thicke has declared the secret to his successful relationship with wife Paula Patton.

The Lost Without You singer has been married to Precious actress Paula Patton for six years, but they have been together since their teens.

At last night's American Music Awards, the 34-year-old crooner told Us Weekly that there is only one way to keep their union together despite having to spend lots of time apart.

"My wife is an actress, a mother, and a wife and I am a husband, a father and a singer so we haven't seen each other a lot the past couple of weeks," he said.

"We won't see each other a lot until Christmas and it's very difficult, but the only thing that gets us by is having great sex together. There is never enough sex. When it does happen, it goes on for hours."

Robin has always been vocal about the couple's love life and called the 35-year-old his "sex therapist" that inspired his fourth album, Sex Therapy.

But he is also complimentary about Paula's maternal skills in his latest album, Love After War.

"Once you see what a woman goes through having a baby, you know what real compassion, understanding, patience, is all about, so that's absolutely what the album is about," he gushed.

Paula is set to star in the fourth Mission Impossible film opposite Tom Cruise.

The couple have one-year-old son, Julian, but Robin says they are not going to give him a sibling any time soon.

"It's not something we are planning on doing," the singer said. "I think anybody who has two babies God bless you!"