Heather Rae El Moussa Opens Up About Relationship with Christina Hall: 'Had Some Ups and Downs'

Heather Rae El Moussa is opening up about co-parenting with her husband's ex.

In conversation with actor and casting director Eliza Roberts and Today's Jill Martin on The New Rules, the pregnant Selling Sunset realtor, 35, talked about building a healthy relationship with husband Tarek El Moussa's ex-wife, Christina Hall, with whom he shares son Brayden, 7, and daughter Taylor, 12.

"I haven't talked about this much because I'm a very happy, positive person, but I felt like I was always second," Heather candidly shared.

"No one ever made me feel that way, but I think when your significant other has such a long relationship with the previous spouse and a lot of love — and it was a very public divorce and you're coming into it. You fall in love with each other, but you always kind of think of the ex. For me, I did," she continued.

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RELATED: See Inside Heather Rae El Moussa's Winter Wonderland Baby Shower for Son on the Way

Noting that she had to learn how to "navigate" those feelings while also learning how to fit into Tarek's family, Heather admitted the arrangement "wasn't always perfect."

"I mean, we've definitely had some ups and downs," she added. "They had ups and downs."

"I think she realized how much I love the kids and that they are number one to me, over anything. So any drama aside, the kids are the most important thing to all of us," said Heather.

Axelle/Bauer-Griffin/FilmMagic, Christina Hall/instagram

Last week, Heather shared a video with a message of gratitude for Thanksgiving, writing, "This year, I'm in disbelief at how much I have to be thankful for- I feel so lucky to be celebrating this Thanksgiving with a growing boy. We will be holding him so soon, It's surreal."

"Feeling so grateful for our health, our growing family, our close friends, and our future. Words don't do it justice and thankful is genuinely an understatement," she added. "This year is the best year yet and I'm thankful for YOU for being apart of it all."

Heather Rae El Moussa/Instagram

The Selling Sunset star also gave fans a glimpse of her holiday meal on her Instagram Stories, noting that she and Tarek, 41, were "missing the kiddos" for Turkey Day, as they weren't there to celebrate with them.

Speaking with PEOPLE ahead of her winter wonderland-themed baby shower earlier this month, Heather praised the support that she's gotten from her stepchildren.

"They are just so loving and caring," the mom-to-be said of the children. "They know that I'm dealing with the back issues and Taylor's always checking on me."

"Every time I moan while moving, she's like, 'Are you okay? Do you need anything?' They've just been so supportive and loving," she added.

Heather also shared with PEOPLE that while she and Tarek haven't chosen a name for their son yet, Taylor has some ideas for her baby brother on the way.

"We're all just getting really excited," she shared. "The nursery is coming together and it's so sweet because we're all calling it 'the baby's room' now, even the kids. It's just really cute."

Tune in to The New Rules Tuesday, Nov. 29 on TODAY All Day, the morning show's streaming channel.