The former tennis star, 44, is pregnant, expecting her fourth baby with longtime partner Iglesias, a source exclusively shares with PEOPLE.
"Anna and Enrique are very happy to become parents again," the insider tells PEOPLE. "They have proven to be great parents to their three children, and both of them love the process. They enjoy the activities and all that goes along with raising children."
The source also tells PEOPLE that the musician cut back his touring schedule in recent years so that he can spend more time at home with his family.
"He loves his fans and loves to tour, but as he has gotten older and become a parent, it has been harder for him to leave," the insider adds. "He will never forsake his fans, but being a dad is very important to him."
The new addition will join the couple's other three children -- twins Lucy and Nicholas, 7, and daughter Mary, 5. The couple had twins, Lucy and Nicholas, in December 2017, and welcomed their daughter Mary in January 2020.
Since becoming parents, Iglesias and Kournikova have continued their low-key lifestyle but occasionally share snippets of their family life. Ultimately, the source says the soon-to-be parents of four are "happiest" at home in Miami Beach.
"Anna and Enrique are happiest when they are home with their family," the source says.
In 2023, Iglesias caught up with PEOPLE and reflected on his longtime love story with Kournikova. The pair met when the former tennis pro starred in the Latin pop superstar's 2001 "Escape" music video.
"[The video changed my life] in ways that I didn't even think about," Iglesias said of meeting Kournikova.
Iglesias said he and Kournikova "grew up" together in the spotlight, which set a solid foundation for their relationship.
"When we met -- although she came from the sports world -- in a way, we kind of got each other. She knew what my world was like. I kind of knew what her world was like. So that understanding helped a lot," he said at the time. "We just started connecting little by little and got stronger and stronger and stronger."
And Iglesias and Kournikova’s kids are the singer’s biggest fans, he added.
"When I pick them up from school and they’re having a bad day or one of them is crying or they’re fighting, we say, ‘Guys, what’s your favorite song?’ And then one breaks out into ‘I Like It,’ and then they all start singing it, and it’s so cute," Iglesias said of his kids’ favorite song from his repertoire. "I’m just enjoying now. I’m enjoying every single day."