The couple tied the knot in 1997, and will celebrate their 24th anniversary on New Year's Eve. They share two kids, Willow, 20, and Jaden, 23. Will is also dad to Trey, 28, from a previous relationship.
"It's hard," she admitted. "The thing Will and I talk about a lot is the journey. We started in this at a very young age, 22 years old... I think you expect your partner to know [what you need], especially when it comes to sex. It's like, 'Well, if you love me, you should know. If you love me, you should read my mind.' That's a huge pitfall."
That behavior is something Jada said she's grown out of, though it can still be "uncomfortable" to express her wants and desires.
"Tell me what you need, tell me what you want, and on top of it, I know that I have to be accountable to do the same. I really try [to do that]. It's uncomfortable, but it's deeply healthy," she said. "[Especially], I think, around sex, because it's something that we don't talk about a lot and there's so much fantasy around it."
When it comes to discussing the topic of sex with their kids, Jada and Gwyneth had very different experiences. For Jada, Willow began asking about sex at age five and she made sure to preach "respect and consideration" when the topic came up with Jaden.
While Jada's "weirdo kids" don't mind talking about sex with her today, Gwyneth's kids -- Moses, 15, and Apple, 17 -- feel differently about the subject. For the actress, the topic first came up when her kids were in sixth grade and had sex ed at school.
"In sixth grade they had the craziest sex ed talk. It was incredible. Full on everything. They learned everything," Gwyneth said of her children, whom she shares with her ex, Chris Martin. "I will never forget Apple's face when she came home. She told them everything. When I say everything, I mean everything."
As for Moses, Gwyneth said that, following that sex ed experience, he hasn't wanted to discuss anything with her.
"He's at an age where we're extremely close, but he's also differentiating," she explained. "He doesn't want me to show him a bra strap let alone ask him a question about a girl... I'm like, 'I'm here if you ever want to talk.'"
When ET spoke with Paltrow earlier this month, she revealed that, when it comes to sex, she advises her kids to "really listen to themselves, listen to their instincts, listen if something feels right, and to act from that place."
"I try always to be neutral on the topic [of sex when speaking to my kids]. I think my generation, we got a lot of messages around sex that made us feel bad about it," she told ET. "I try to just be curious, and teenagers are never going to want to talk to their parents about sex, ever. I sort of follow their lead and luckily, in middle school they had a very thorough sex education, so the school handled the kind of birds and the bees parts. Then I am there for any questions, but the questions are pretty minimal."
"I think the main thing that nobody ever tells you, is you have to stay really close to your own truth and you have to stay really in integrity with that truth," Paltrow added. "Because when you are in a relationship and you are not being your full self, you are sublimating things or you are white knuckling through something, and I think it can be pretty damaging to how you feel about yourself."