'The Bachelor': Sean and Catherine Lowe on the Secret to Their Successful Marriage (Exclusive)

Sean and Catherine Lowe are one Bachelor couple who made it. While a handful of other Bachelors have ended up with another woman from their season, after 18 years and 24 seasons, Sean remains the only male lead to marry his final pick. As he told ET's Lauren Zima on Monday, there's a reason for that -- or "two or three."

"One, my wife selflessly decided to move -- leave her family, her friends, her job, her life as she knew it in Seattle to come live in Dallas," Sean explained. "Every season, the people that end up together usually don't live in the same city, so somebody has to make that sacrifice. That's extremely hard, so I give Catherine all the credit in the world for that." 

Next, Sean thinks their Christian faith "has a lot to do with" their lasting marriage. "Just the commitment, 'Hey we're going to start our marriage on this foundation of God and grow together, and commit to grow together no matter what. I think that's helped tremendously," he said. 

"And then, I found my best friend. On the show, we would say, 'Wouldn't it be nice if we could just put sweatpants on and lay on the couch and watch Netflix?' That is who I found, as opposed to just picking someone just purely based something superficial," Sean added. "So, I think those are three pretty good reasons why it's been able to work for us." 

Sean and Catherine's love story was revisited on Monday's premiere of The Bachelor: The Greatest Seasons -- Ever! The three-hour episode showed the pair's road to engagement... as well as the drama Sean went through to find his true love. 

"It's kind of funny, I thought we would've ridden into the sunset a long time ago and people would've forgotten about us," said Sean, whose season aired in 2013. He married Catherine in a televised wedding the following year. "So, to relive it and rehash everything and the spotlight being on us momentarily, it's kind of a blast from the past." 

"It's a little weird to watch your husband kiss other people," Catherine confessed with a laugh. "But knowing that it was kind of who we were at the time, just bringing that into perspective and knowing what we have now, it's fine. And I just love looking at the memories that I had with the girls and the fun times that we had."