"It's actually funny," he told PEOPLE Now when asked if he has any advice for Fletcher, 25. "I'm actually friends with her brother back home in Dallas. Talking to him, he said that she was kind of nervous going in, didn't know what to expect."
Lowe, 32, who met his wife Catherine on The Bachelor after a turn on The Bachelorette, kept his advice simple.
"Have fun, go in there with an open mind, an open heart," he said. "Have fun, enjoy it and if you're lucky, or I should probably say blessed, you might find someone as good as I did. Find your life partner."
Added Catherine, "Yeah, and then we can hang out together in Dallas."
The couple knows a thing or two about relationship advice after they signed up for Marriage Boot Camp last fall.
"I don't think we needed it," says Catherine, 30.
"There are certain things that you can look back [and think], 'Oooh, I wish I wouldn't have done that – hindsight.' We didn't even need hindsight for that," Sean says with a laugh. "I walked into that house, and I thought, 'What did we do? We should not be here.' "
He acknowledges, "The counseling aspect was awesome – they give you tools to help strengthen your marriage. The crazy people yelling 24 hours a day? Not so much."
The couple – who are expecting their first child, a son, soon – also offered some wisdom for The Bachelor's newest fiancés Ben Higgins and Lauren Bushnell.
"I think the most important thing is you just have to commit to each other," advised Sean. "It's going to be tough, you're going to face all kinds of challenges and obstacles. Commit and don't let these distractions get in the way, and you'll be fine."
The Bachelorette premieres May 23 on ABC.