Brandi Redmond’s fertility struggles were well documented on season 2 of The Real Housewives of Dallas. But when season 3 premieres this summer, she and husband Bryan will have a surprise for fans: infant son Bruin Charles, whom the couple welcomed through adoption this past winter.

“It’s changed our lives forever,” Brandi tells PEOPLE exclusively of their new addition, who joins daughters Brooklyn, 9, and Brinkley, 6. “We are obsessed with him, my whole family is. We’re just so blessed.”

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The couple’s son — born prematurely on Dec. 31, weighing 4 lbs., 5 oz., and measuring 18 inches, and adopted via a closed adoption — has been a “perfect fit” for the family.

Bruin even has strawberry blonde locks, which match the brood of Redmond redheads. “It’s crazy,” Brandi says. “He’ll always look like he came from me, which he did — he came from my heart.”

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Image zoom Brandi Redmond, Bryan Redmond and baby Bruin Charles Stephanie Rose Photography

Since meeting him, Brandi hasn’t stopped smiling — and neither has Bruin.

“He’s so, so happy,” Brandi says. “From the moment that I met him for the first time, he just looked straight into my eyes, held my finger as tight as he could, and let out this giant grin. And it’s been like that ever since. He smiles all the time and just giggles and laughs.”

“The only time he cries is when he’s left alone,” she adds, choking up. “I’m sure that’s a normal baby thing, but because of how we got him, I’m especially like, ‘No, you will never be left alone.’ ”

Image zoom Bruin Charles Redmond Stephanie Rose Photography

If Brandi is getting emotional, that’s because Bruin was a bit of an unexpected addition to her family.

After failing to conceive another child, Brandi and Bryan reluctantly made the decision that they were going to stop trying for baby No. 3 — a tough call since Brandi always felt like her family was missing something.

“For a long time, people would tell me, ‘You’ll know when your family is complete.’ And I never felt that way,” Brandi explains. “I’m blessed to have two beautiful children, but even after having them, in my heart, I knew it wasn’t complete.”

“So we tried again for years,” she continues. “But my fertility was on the decline, and in October, Bryan and I said, ‘You know what, we’re not going to even try anymore.’ I turn 40 in July, and there are so many risks. We just said, ‘Our family is fine with the four of us.’ Adoption wasn’t even on our minds, even though one of my own brothers is adopted. We just walked away from it all.”

Image zoom The Redmond Family: Brandi, Bryan, Brooklyn, Brinkley and Bruin Jennifer Yarbro Photography

But days into the New Year, that changed. Just coming home from a family vacation, Brandi got a call from a friend connected to a social worker who told them about Bruin.

The boy’s biological parents were teenagers, who awarded him to the state at birth. Without a plan in place, social workers were having trouble finding a family who wanted a son — until they were led to Brandi and Bryan.

“It happened pretty much overnight,” Brandi recalls. “He was in the neonatal intensive care unit because he was born prematurely, so we flew out of Dallas — he was still in Texas —and we met him in the hospital. We just immediately fell in love.”

“That connection was there right away,” she adds, remembering how hard it was to say goodbye to him after that first visit. “He had to stay in the NICU for a little longer so when we left the hospital and I had to fly back home, I cried for six hours because I was leaving him. I just wanted to be with my son.”

Image zoom Brandi Redmond F. Scott Schafer/Bravo

Fans will get to see Bruin’s adoption on the next season of RHOD, the cameras following the emotional journey. “They followed the whole thing from start to finish,” Brandi says. “It’s a beautiful story. It’s crazy because they captured the rollercoaster of emotions we go through.”

That includes some of the struggles Brandi experiences while adjusting to being a mom of an infant again.

“My maternal instinct kicked in so naturally, which is amazing, but you’ll see that I’m having to relearn some things,” she jokes. “Everything changes in the baby world! Everything is a lot easier now, even though I want to make it a lot harder! I’m like, ‘How do I not know how to work these things?’ ”

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One thing that came easy: coming up with Bruin’s name. For the moniker, Brandi and Bryan went back to a favorite name they almost used on their youngest daughter.

“When I was pregnant with Brinkley, the doctor’s said that she was a boy and my husband always loved the name Bruin,” Brandi says. “My husband’s into sports and I think he’s a UCLA fan [despite the fact that] he didn’t go there. And he just loved that name. So Brinkley was ‘Bruin’ for a little bit until they said, ‘Oh no, it’s a girl.’ ”

Charles, Bruin’s middle name, is a “family name.”

And speaking of family, Brandi now says that hers is right where she wants it. “My family is complete. One hundred and ten percent complete,” she says.

“His biological parents, I just think they were so brave to make the best decision for him. I’m very honored and excited that he’s a part of our family now,” Brandi continues. “He’s our miracle baby. Things happen for a reason and God gives you exactly what you can handle. This was just meant to be.”