The source added that Boss' inner circle is in "disbelief" that the DJ is gone.
As OK! previously reported, the TV star was found dead in a Los Angeles hotel, and Holker, 34, later confirmed the news via a statement.
"It is with the heaviest of hearts that I have to share my husband Stephen has left us," Holker, who shares daughters Weslie, Zaia and son Maddox, confirmed. "Stephen lit up every room he stepped into. He valued family, friends and community above all else and leading with love and light was everything to him. He was the backbone of our family, the best husband and father, and an inspiration to his fans."
"To say he left a legacy would be an understatement, and his positive impact will continue to be felt," she continued. "I am certain there won't be a day that goes by that we won't honor his memory. We ask for privacy during this difficult time for myself and especially for our three children."
Prior to Boss' death, Holker gushed over the pair's recent milestone.
"It’s our 9th anniversary!! I couldn’t be more grateful to celebrate this perfect magical day!!! Saying YES to @sir_twitch_alot has been one of the best decisions I have ever made in my life!! I feel so blessed and loved!! I love you baby and I will never take you or OUR love for granted! I LOVE YOU #happyanniversary #bosswedding2013," she captioned a video of the two lovebirds via Instagram on December 10.
One day later, the TV host, 34, also shared a video of herself and her man dancing by the Christmas tree. In the video, the two, who are both professional dancers, boogied alongside their Christmas tree. "HOLIDAY SUNDAY FUNDAY DANCE !!! With my lover @sir_twitch_alot #thebosshouse #holidayfun #dance #bossstudios," she wrote.