"I have been so open and truthful in this relationship – it is amazing," she tells PEOPLE at a signing of her new book, Love, Lust & Faking It: The Naked Truth About Sex, Lies and True Romance, Friday at Miami's Epic Hotel.
"If he wants Chinese [food] and I don't, I say it," she says. "If he wants to go out and I want to stay in and watch Dancing with the Stars, I tell him so … Sometimes we both want to play poker and we have a blast at home."
Adds McCarthy, 37, "Our relationship is stronger because of the honesty."
Part of this newfound self-assurance came after breaking up with longtime boyfriend Jim Carrey and beginning to think about her book.
"I got the book deal the same time Jim and I split after five years together,” McCarthy says. "While researching and writing it, I looked inside of myself and began to see what was wrong with me instead of blaming him for everything."
"I was a girl who pretended. I would say I liked things when I didn't," she says. "I knew if I wanted to grow, I needed to make myself happy before I could begin to have an equal relationship with another man."
And life with Toohey, 35, a Las Vegas-based pirate performer, is good indeed.
"With Jason, I went in with all of my chips laid out," she says. "He respected that and saw the life in me. And, so far, it is working well."
McCarthy is also pretty busy. In addition to her new book, she's readying a talk show for Oprah's Harpo Studios, which begins shooting in April.
"I am so pleased with everything in my career and personal life right now," she says. "I am staying with Jason because I am happy. If that should change, I will simply leave. I trust my own happiness – and I will follow my own emotional guide."