New York, New York - Lindsay Clancy's ex-husband Patrick has opened up about her shocking murder trial, the devastating deaths of their children, and his life after the tragedy.

Patrick Clancy sat down with 60 Minutes for an interview that aired Sunday night – his first since Lindsay's murder trial ended in a mistrial earlier this month.

He said that in late 2022, Lindsay was struggling with insomnia, a "deep" depression, and intrusive thoughts.

"I think mental illness has this ability to be tragically deceptive. So I'm sure there are things that I didn't see," Patrick said.

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In early January, Lindsay checked herself into McLean Psychiatric Hospital, and after receiving treatment for depression, she returned home and celebrated their daughter Cora's 5th birthday.

But just two weeks later, Patrick returned home to find that Lindsay had strangled their three children before cutting her throat and wrists and jumping from the upstairs window in an attempt to take her own life.

Patrick said he knew immediately that Cora and three-year-old Dawson were dead, but first responders were able to revive eight-month-old Callan's heartbeat. He survived for four days before passing away in his father's arms.

"I'm so grateful for those four days that I had with him. And I'm so grateful he hung on," Patrick said.

In the wake of the tragedy, Patrick came across headlines about the killings that referred to Lindsay as a "killer mom" and a "monster."

Patrick decided to speak out in defense of his former spouse: "None of them were accurate. I believe that it was her mental illness that caused that."

He added that while Lindsay did not ask for his forgiveness, he offered it anyway, as he felt he "would be eaten up inside forever" if he never did.

Elsewhere in the interview, Patrick touched on the online firestorm that erupted amid Lindsay's murder trial, including a flood of unfounded theories that he was somehow behind the killings.

"It's deeply harmful to the legacy of my children," he said. "It is a huge distraction from what really matters here, which is perinatal mental health. And it's done real harm to real people, myself included but also others."

Patrick added that the conspiracies have been "painful to see," saying, "It makes it difficult to be in public, and it's possible that some of those people, after seeing lie after lie after lie, they start to believe it, and that's what we're left with."

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His lawyer previously threatened anyone sharing "false, defamatory statements" about Patrick, saying that they should be "on notice" for possible legal repercussions.

Patrick further addressed some of the specific claims that fueled the theories, including his demeanor on the witness stand.

While some online alleged that he seemed stoic or even unemotional, the truth was the complete opposite.

"On the second day, a lotta that was focused on the night of January 24. We did take a break right before they played the 911 call, which I knew was gonna be just horrific," Patrick explained.

"I went to a back room, and I started having this massive traumatic panic attack. My heart was pounding."

The year after the killings, Patrick moved to New York, where he met Dr. Rachel Denis through a local running club.

The pair quickly struck up a connection, and Rachel learned about his devastating losses after seeing a photo of the children that Patrick used as his phone wallpaper.

Patrick said that Rachel has helped him carry the immeasurable weight of his grief.

"I know I can't fix – I can't bring his kids back. But if I can honor them and allow Pat to grieve but also just continue to honor them in the present, it – I guess that's all I can do," Rachel said.

The pair tied the knot back in April, and they are now planning to start a family.

"I can't wait to tell them about their brothers and sister," Patrick said.

If you or someone you know needs help, please contact the 24-hour National Suicide Prevention Hotline by calling or texting 988 for free and confidential support. You can also text "HOME" to 741741 anytime for the Crisis Text Line and access to live, trained crisis counselors.