"I could have spent the rest of my life with Tom and not be married, but I wanted to call him 'my husband'," the Hot in Cleveland star, 50, tells PEOPLE. "I really wanted to share how I feel about Tom with the people I love."
When the pair – who became engaged in May – exchanged vows in a surprise ceremony at their cliff-side Malibu home on New Year's Day, Bertinelli was surrounded by about 100 family members and friends, including her 19-year-old son Wolfie, ex-husband Eddie Van Halen and One Day at a Time costars Mackenize Phillips and Pat "Schneider" Harrington.
Wearing a custom blue silk chiffon gown by David Meister and Jimmy Choo shoes, the bride says: "I'm happier than ever!"
For the exclusive wedding album and all the details – The vows! The gown! The food! – pick up the new issue of PEOPLE, on newsstands Friday