"[Catherine] had dreams to be a mother, and would always tell me that's what she was born to do," he says

David Nail became a first-time dad in December to twins Lawson Brent and Lillian Catherine. And now, he’s opening up about the fertility struggles he and wife of seven years Catherine endured on their multiple-year journey toward expanding their family.

“A lot of what we dealt with had to do with me,” admits the country singer, 37, in a video for his website’s #Fighter series, which premiered Wednesday and will lead up to the Friday release of Nail’s album Fighter. “As a man, you definitely don’t want to hear that.”

Aside from Nail’s video — in which he and Catherine discuss their fertility issues and Nail’s past experiences with long-term depression — the six-episode series will run inspirational “fighter” stories from everyday people who have conquered hurdles in their own lives.

The “Night’s On Fire” crooner also recounts his thoughts behind their decision to implant two embryos, regardless of the risk and difficulty involved in potentially having and raising twins.

” ‘It’s been this difficult … if we are so lucky to have two, it may be the only two we ever get,’ ” Nail recalls saying.

David Nail Family Photo Fighter Series

Courtesy Nail Family

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Though Nail admits it got to the point where it felt “like everything was stacked against” the couple, the time and effort involved in trying multiple procedures was worth it — for both of them.

“[Catherine] had dreams to be a mother, and would always tell me that’s what she was born to do,” he says. “So in whatever way I was [contributing to that not] happening was beyond frustrating.”

Catherine adds it was “insult to injury” for her husband after finding out the cause of their conception issues right around the time Nail’s depression was diagnosed. But she adds she would go through the entire fertility treatment process again.

“Your eye is on the prize, and that’s just what I kept telling myself every single day: ‘What’s the end result?’ ” the new mom says. “Yes, this may hurt for now, but I would do it again. I would do it 10 times again to get what we have now.”

The couple also shares the stories behind the moments Catherine found out she was pregnant, breaking the news to her husband and the day their children were born.

“I had a pretty decent idea of what I was about to witness but I had, at the end of the day, no clue,” Nail says about his experience during his wife’s labor and childbirth. “I can remember [the doctors] counting the needles and counting the knives and the tools.

“I can remember her shaking,” he adds, continuing emotionally as both he and his wife tear up. “And then you hear somebody cry.”

Nail also admits that he knew his life had just changed in the best way immediately upon the arrival of Lawson and Lillian.

“It’s the beginning of a new journey, but it’s the end of this tremendous struggle that we had gone through for so long,” the singer says of his thoughts following the moment he became a father.

Fighter comprises 11 tracks total — including one called “Babies,” a tribute to his twins.

“The most important part of the song was to let them know, ‘Hey, this wasn’t just some Tuesday night [where] we went out to dinner and came home and nine months later you were here,’ ” he shares. ” ‘This was a lot of prayer, a lot of work, a lot of frustration, anger, fights.’ ”

He continues shakily before wiping a tear away, “You just want them to know that it wasn’t easy, but [you’d] go through it 15 times just to experience that moment again.”

In a press release for the album, Nail gets honest about what writing and recording the album meant for him.

“I truly believe this album, from top to bottom, is the first time I have been able to tell my story in real time of where I am right now as an artist, a husband and a father,” he confessed.

“I wrote more songs for this album than I have for any of my other three so it’s already more personal. Fighter speaks to my journey, my life and now to where I am personally and professionally.”

For more inspiring stories from the Fighter series, go to fighter.davidnail.com.

Jen Juneau