Idina Menzel Opens Up About Her IVF Journey: 'It Just Wasn't Meant to Be'

Idina Menzel is pulling back the curtain on her journey with in-vitro fertilization (IVF).

Ahead of her documentary Idina Menzel: Which Way to the Stage?, Menzel spoke with PEOPLE about undergoing IVF on tour, and why having another child ultimately "wasn't meant to be."

The Tony winner has one son, 13-year-old Walker, with ex-husband Taye Diggs. Three years after her and Diggs' 2014 divorce, she married actor Aaron Lohr, and having kids wasn't initially in the new couple's plans.

"Maybe before meeting me, [Lohr] didn't think he wanted to have kids, and then he sees how good of a dad he can be," Menzel tells PEOPLE. "So I wanted that for him."

In the Disney+ documentary, which shows a mix of moments from Menzel's life and her 2018 national tour, the singer reveals that her feelings about having more kids changed along with Lohr's: "I didn't think I wanted to have a baby but then Aaron has been the most amazing man to my son."

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The documentary cameras go backstage with Menzel, following her from venue to venue, but also join her at doctor's appointments and in the vulnerable moments following her IVF treatments.

"I'm literally going through stuff that I'm shooting into my body and I don't know how that's going to affect my voice," she says, reflecting on the "balancing act."

"And it may force me to make extra trips to get back and forth to the doctor in addition to making trips to get home to my family," she adds. "And all of that isn't great on your body when you're trying to have a baby."

The "Let It Go" singer tells PEOPLE that her choice to include these "emotional" and "physical" moments in the film, which was originally just going to be a standard tour documentary, wasn't contingent on whether she was ultimately able to become pregnant.

"No matter what the outcome, I just wanted women to feel seen in this film and people to understand what we go through," she says. "It was important to me to forgo the privacy of that and allow people to have a little window into that experience."

Four years after wrapping the tour, Menzel says she's content with the results of her IVF journey, noting that she and Lohr have "moved beyond that."

"I have this amazing son and I was fortunate enough to have him," the singer says. "And the pregnancy was pretty easy and I conceived easily, and there's a lot of people that don't even get to have that."

Menzel also shares that Lohr "feels really loved that I even tried and put my body through that."

"I think going through all that, you're so exhausted by it that finally, it becomes apparent like, 'I don't want to do this anymore and it just wasn't meant to be,' and you're resolved in that," she says.

"He sees Walker as his own kid at this point anyway," she says of Lohr. "I think we feel content and lucky with what we have."

Idina Menzel: Which Way to the Stage? premieres Dec. 9 on Disney+.