The singer and TV personality announced Friday they had wed earlier this week in Aspen, Colorado.
Fuentes also shared the news on her Instagram account, writing in English and Spanish the same message: "This happened & I couldn't be happier. Nos casamos y más feliz no puedo estar #myhusband @therichardmarx."
Fuentes, 49, and Marx, 52, began dating in 2014. The model even starred in his music video for his 2014 song, "Beautiful Goodbye."
This is the second marriage for both.