Brittany Maynard's Husband 5 Years After She Ended Her Life Amid Cancer: 'I'm Immensely Proud'

It’s been five years since Dan Diaz lost the love of his life Brittany Maynard amid her terminal cancer battle, but in many ways Nov. 1, 2014 feels like it was just yesterday.

Maynard was a 29-year-old newlywed and couldn’t have been more excited for her future before she was diagnosed with brain cancer and given six months to live. As her suffering continued to increase she decided to utilize the prescribed fatal dose of barbiturates which would end her life instead of allowing the horrible symptoms of the illness to run its course.

Maynard didn’t end her battle without fighting for others. She became an advocate and activist for the right-to-die movement, which gave her the chance to end her life on her own terms.

“I’m immensely proud of her legacy and of her determination to speak up even as she was navigating the chaos of that disease,” says Diaz, now 48.

With Compassion & Choices, an end-of-life advocacy organization, she tirelessly worked to expand death-with-dignity laws around the country.

“My glioblastoma is going to kill me and that’s out of my control,” she told PEOPLE after her diagnosis. “I’ve discussed with many experts how I would die from it and it’s a terrible, terrible way to die. So being able to choose to go with dignity is less terrifying.”

In June of that year, she moved from California to Oregon with her husband Diaz, her mother Debbie Ziegler, and her stepfather Gary Holmes, so she could have access to the state’s Death with Dignity Act, which allows physicians to prescribe life-ending medication to certain terminally ill patients.

Before her death, Diaz told his wife that he would continue working to get the law passed in more states. When Brittany died, it was available in Washington, Oregon, Vermont, and Montana. Five years later it’s available in nine states — including California, Colorado, Hawaii, Montana, Maine, New Jersey, Oregon, and Vermont — plus Washington D.C.

“I promised Brittany that I would help work on this legislation in other states so that nobody would ever have to leave their home, like we did, after being told you have six months to live,” he says. “I still continue to get meetings with elected officials because of their recollection of her. It is absolutely her story that makes an impact, and continues to resonate.”

RELATED: Terminally Ill Brittany Maynard Thanks Those Supporting Her ‘Death with Dignity’

Looking back, Diaz sees how much the general public could relate to her story, he tells PEOPLE.

“She wasn’t a 92-year-old geriatric patient who’s dying,” he says. “She’s this young, well-spoken individual who’s simply saying that she doesn’t want to have to endure what the final few days or weeks of her life might be with the effects of that brain tumor. She wanted to have a little bit of control of how those days play out.”

Diaz continues to make a significant impact on legislators across the country and has been to 14 state capitals and Capitol Hill. He also travels to educate the general public at rotary clubs, assisted living facilities, palliative care conferences, high schools, and colleges.

While he continues her fight, not a day goes by that Diaz doesn’t think of Maynard and the life they could have had together.

“What I miss are just all those moments: her smile, her laughter, the sound of her laughter,” says Diaz, who lives in the same house he bought with Brittany in 2012. “That stays with me always. She was just a caring, loving person. The plans that we had made together to have a family, children, all of those things. Little projects that she wanted done around the house. Those things that, I guess, we all just kind of take for granted, or sometimes don’t consider to be anything significant. Those are the things that will come into my mind and bring a smile.”

He thinks back to her strength during her final few months and “her decision to speak up during a time when it would be normal and understandable for most people to become introspective.”

“Brittany instead decided to speak up for terminally ill individuals, in her predicament, who maybe they don’t have a voice or a platform,” he adds. “They say that the things that you do for yourself are gone when you’re gone, but the things that you do for other people, that’s your legacy, that’s what lives on.”