Pinkett Smith, 50, was joined by her mother Adrienne Banfield-Norris, 67, and Oscar-winning actress Gwyneth Paltrow in the latest episode and said maintaining a strong relationship after decades together is "hard".
She said: "The thing Will and I talk about a lot is the journey. We started in this at a very young age, you know, 22 years old.
"That's why the accountability part really hit for me because 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."
Paltrow, whose new Netflix series Sex, Love & goop explores intimacy, agreed and said: "Isn't it weird, though? It's like someone doesn't read your mind and we feel crushed."
Pinkett Smith, who met her husband on the set of The Fresh Prince of Bel-Air, said "I really try" to maintain open communication with Smith, 53.
She added: "It's uncomfortable, but it's deeply healthy and I think around sex, because it's something that we don't talk about and there's so much fantasy around it."
The Smiths' marriage is often in the headlines. Men In Black star Smith revealed in September his wife was not the only one who had had an extramarital affair.
That came after Pinkett Smith revealed she had an "entanglement" with rapper August Alsina while separated from her husband.