Season 17 Bachelor Sean Lowe cautioned Bachelorette Andi Dorfman not to think of new fiance Josh Murray as her "soul mate," writing in a blog post that it "sets everyone up for unrealistic expectations" Credit: D Dipasupil/FilmMagic; Frazer Harrison/Getty Images

Sean Lowe has been there, done that. As the only one of ABC's 17 Bachelors who married the woman he chose on the finale, Lowe has some advice for the franchise's newest couple, Andi Dorfman and Josh Murray, who got engaged on the season 10 finale of The Bachelorette

In a blog post titled "Dear Andi, Josh Is Not Your Soul Mate," Lowe offered both his congratulations and his hard-won wisdom to Dorfman and her fiance. "I couldn't be happier for the new couple and wish them nothing but love and happiness going forward," he wrote, adding that Murray's proposal in the Dominican Republic reminded him of his own proposal to now-wife Catherine Giudici in Thailand.

He went on to talk about what the blissfully-in-love duo should expect now that their engagement is public. "You see, what Andi and Josh don't know is that they are just now embarking on the hard part. Nobody told Catherine and me that our toughest challenge would come after we rode those elephants off into the sunset," he explained. "Falling in love while globetrotting the world was the easy part. Learning how to love someone you've spent a collective 20 hours with is the really hard part."

His advice? "I think I'd tell them that the post-show/pre-marriage time frame will be one of the most challenging. But mainly, I'd tell them not to elevate the other to the level of 'soul mate,'" he wrote. "It sets everyone up for unrealistic expectations and emphasizes the romance over the hard work of building a relationship."

Lowe and Giudici are happily married, but "it's definitely taken work," he added. That said, he and his wife "are so excited for Andi and Josh" and whatever lies ahead for them. "[We] hope this time without the lights and cameras will bring them ever closer to the time when the minister pronounces them—not 'soul mates'—but 'husband' and 'wife,'" he concluded.