"I just fell to the ground," he told People. "It was the worst moment of my life."
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Christina, 38, was a basketball coach who served as an assistant under Bryant on the travel team that featured Gianna. They were en route to a basketball game at Bryant's Mamba Sports Academy in Thousand Oaks, California, when the crash occurred in Calabasas.
Christina and Matt Mauser both taught at Harbor Day School, the Southern California private school where Bryant’s daughters were enrolled. Mauser is now tasked with raising the couple’s three children, Penny, 12, Thomas, 10, and Ivy, 4. He says moving on has been a challenge for the family, which resides in Huntington Beach, California.
"I find myself having better days. I've gotten better at just kind of moving through the grief," he says. "The kids all have different responses. I've tried to show them that it's okay to be sad and vulnerable. Sometimes we just need to cry these things through."
Mauser says losing Christina was devastating, but he has to remain strong for their children.
"My wife was my compass. My gift," he says. "I had 16 years with this amazing human being who taught me more than anybody else. And now I just have to be able to do that for my kids."
Mauser also wants others to remember his wife and is launching the Christina Mauser Foundation, which will offer scholarships to young female athletes who need financial assistance.
"I don't want my wife to just go unnoticed," he says. "I'm trying to honor what she would want."
A musician who sings for a Frank Sinatra cover band, Mauser has written songs to cope with the loss of Christina.
"Being able to express how I feel on paper as a song, and writing music has been very helpful for me," he says.
Mauser also the one who connected his wife with Bryant. He was writing music for the NBA legend’s podcast, “The Punies,” and introduced them when the Lakers great was looking for an assistant coach.
Mauser says his wife flourished as a coach noting she “was becoming the person she was meant to be.”
“(Kobe) gave her a lot of respect and let her do her thing," he added. "She felt really empowered."