Designer Nate Berkus says he thinks about former boyfriend Fernando Bengoechea all the time.

Speaking to his former mentor, Oprah Winfrey, in the second part of a two-part interview which aired Sunday on cabler OWN's Super Soul Sunday, Berkus, 41, explained why he dedicated his new design book, The Things That Matter, to his late partner.

Berkus lost Bengoechea in 2004 while the couple vacationed in Sri Lanka. Bengoechea, a photographer, is presumed dead from a tsunami that hit the island country.

“You know I think about it all the time,” Berkus said. “Where would we be had he survived? Would we still be together? Would he have agreed with the decisions that I've made since then in life? What would he think about who I am today? 'Cause it's certainly different than who I was in 2004.” (The video is embedded on this page. Visit our video library for more videos.)

Berkus also said that surviving the tsunami changed him and that he likes himself more today than before the tragedy.

“I really don't recognize the person that I was before the tsunami. And everything that I've learned from that experience, really everything, I wouldn't trade. I really trust myself. And like myself.”

The tsunami even affects his new romance: “I see myself behaving in a way with my new boyfriend that is fear based; that something will happen to him.”

(Related: Nate Berkus says witnessing boyfriend disappearance was a gift.)