The 33-year-old star went missing on Wednesday (08Jul20) after taking a boat ride on the lake with her four-year-old son Josey. While he was found on the boat three hours later alone, Naya never made it back to the vessel, and the search for her remains ongoing.
Taking to Instagram, Mowry shared how he's holding onto hope that she will be found, admitting that he's never stopped loving her.
"My sweet Naya - to say that I am devastated would be an understatement. This is a nightmare. Everyday (sic) gets harder. However, I am holding onto hope that you will be found," Mowry began, explaining how they grew up and became adults together.
"We experienced so many firsts together. You were my first experience with everything; love, intimacy, heartbreak. We broke each others hearts and then mended them back together... more than once.
"I will never not think of you. No woman has ever measured up (to) what you gave me or how you made me feel. I’ve never liked to admit it but I have never stopped loving you," he confessed. "A part of me always wished for the day where God would bring us back together to be what we dreamt we could have been."
Mowry also extended prayers to Rivera's family, telling the actress' brother Mychal and sister Nickayla that they will always be "like younger siblings to me," and added to her parents Yolanda and George that "whatever you need I am here for you. We are forever family and I love you."
"I still have faith. I still have hope. Let's please all pray that she is found and brought home safely," he concluded. "I love you forever. I always have and I always will."
The star didn't reveal when the pair dated, however they were both child actors, and together appeared on Mowry's show "Smart Guy" in 1997 and 1999.