The grief left him debilitated for the first two months, until one day, the performer woke up and picked up his guitar, leading him to the studio where he recorded his first song about the experience called "Lost."
It started to help him heal, which is why he turned his focus to writing and recording. Now that it's been a year, he sat down with Eyewitness News at 17th Street Recording Studio in Huntington Beach to share how he and the kids are doing.
"It's a process, you know. We're not gonna be better in a year. Who knows if we'll ever be fully healed," he said. "It's a wound and it's gonna take time to get that wound to the place where we can function again, but it's never gonna go away. You're never gonna be ok with losing your mom. You're never gonna be ok with losing the love of your life."
Mauser says he still thinks the hardest part was telling the kids what happened.
"That was the worst, worst point of my life. Being there for my children and having to just be honest with them about their mom not coming back. That was painful," he said.
Even though the "what ifs" still haunt him, Matt says he's learned to remember that everything he did up until Christina's death, he did out of love.
"But of course, I do run through certain scenarios in my head. I wish I would've woken up, I wish I would've been able to tell her I loved her one last time, I wish I would have seen the fog," he said
Despite the continuous grief, he's grateful to say they're moving forward and finding joy in life with some silver linings, including a deep understanding of his kids and his renewed confidence as a parent. Plus, his ability to embrace what he calls "sweet pain."
"I'm finding myself having a closeness with her in spite of her not being here. I still feel her in my heart, I still hear her voice, I still hear what she would want me to do and how she would want me to handle situations."
He was able to find that sweet pain through his music, allowing him to purge the emotions like in his newest song, "When You Wake Up and She's Gone."
"The lyrics go, now the coffee pot's set to a cup just for one. My new morning routine when the day has begun," he said.
Tuesday, on the one year anniversary, he's honoring Christina with a live tribute concert.
"When you're struggling, when times get tough, you do the things that you know. To give yourself a sense of stability in life. So for me, singing is what I know. Performing and playing with my band is what I do," said Mauser.
The concert will benefit the Christina Mauser Foundation, which he created in her honor. He hopes to create scholarships for women and girls in sports, something she herself had hoped to do one day. While his tribute will benefit others, he knows it will also play a major role in his healing process.
"We're human beings, we need joy in our life and we're supposed to be happy. I fight everyday to find happiness. It's very much a struggle, but you have to actively find happiness and do the things that bring you joy," he said.
The tribute concert airs live on MattMauser.com Tuesday at 5 p.m.
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