He said: "It was the last gift to be opened and I wrapped it in seven different boxes so Camila would have to keep unwrapping."
Matthew - who has two children, Levi, three, and two-year-old Vida, with Camila - says once the brunette beauty found the ring, he got down on one knee and popped the question.
He told People: "She got the ring, I took a knee and asked her to marry me and take my name. After a bit, she conceded ... thankfully."
The couple - who have been in a relationship for five years - married at their Texas home on June 9 and the couple are excited about what the future holds.
Matthew said: "We decided to embrace the ritual of marriage as an opportunity and adventure we'll take together."