Arie starred onThe Bachelor's 22nd season and proposed marriage to Becca Kufrin during the finale, only to dump her weeks later on-camera and beg his runner-up, Lauren Burnham, to take him back.
Arie and Lauren have since reconciled, gotten engaged, and moved in together in Arizona. And the couple is now planning an early 2019 wedding in Hawaii.
"I don't think Arie will go down in history as maybe the most popular Bachelor. He may have had one of the more unpopular decisions," Sean toldUs Weekly in an episode of the magazine's In Case You Missed Us podcast.
"I think in that environment, it's so weird and you lose touch with reality. You're filming a show, but you're also making these really hard gut-wrenching decisions," Sean explained.
"I think he just made a bad decision in not choosing the right woman and he realized that and he knew he would receive a ton of backlash, and he still decided to call that relationship off, which, let me say this, he should not have done that on camera."
Sean, 34, just welcomed his second child, two-week-old Isaiah, with Catherine, and he hopes Arie will find the same happiness and joy with Lauren.
Sean claimed the 36-year-old pro racing driver ultimately made "the right decision" for him. The father of two also revealed he'll definitely be attending Sean and Lauren's January wedding in Hawaii.
"Arie is a great friend of mine," Sean noted in the podcast.
In the meantime, Sean is watching Becca's season of The Bachelorette unfold on ABC. Sean told Us that Becca "has a good head on her shoulders" and will "hopefully end in another successful relationship."
Becca did, after all, already reveal she is happily engaged and in love.
"Doing everything on camera, that's really easy because you're out of touch with reality and you're staying at these five star hotels and you're traveling the world and it's all about love and everything is great," Sean recalled of The Bachelor experience.
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"And then post-Bachelor most likely you've ended up with someone who doesn't live in the same city as you. So you have to figure out... You're wrestling with, 'How do I cultivate this relationship that was formed on a reality TV show?'"
Sean confessed being engaged in the real world after the show can be "very challenging" but commitment and effort is key.
"I think if you... make your relationship your No. 1 priority and everything else is secondary, it's a lot easier," he noted.
Becca previously teased that Arie will make an appearance on her The Bachelorette edition and the interaction will change their lives forever.