Jason Campbell and Jenny Montes in their engagement photo. (Jermaine & Catron Turner / JPix Photography)

Experts agree: Calling off a wedding at the last minute may be embarrassing, but it’s almost always for the best.

Still no word why Jason Campbell and Jenny Montes decided to pull the plug on their wedding Saturday just hours before the ceremony. Guests of the NFL quarterback and his fiancee got the news (but no details) when they arrived in the Dominican Republic for the party.

Canceling a big wedding causes plenty of heartache (and gossip), especially when big names are involved. The tabloids went crazy when Playmate Crystal Harris jilted Hugh Hefner just days before their trip down the aisle. Everyone still remembers how Julia Roberts left Kiefer Sutherland three days before their 1991 wedding. Tough calls, but better than going through a wedding for the wrong reasons. Exhibit A: Kim Kardashian, who’s been savaged for what critics call her sham marriage with Kris Humphries for the millions generated by the wedding.

How does it get that far? Couples get caught up in the romance and fun of a dream day, said wedding planner Jennifer Stiebel: “You get caught up in the whirlwind of it.” The closer the date, the harder it is to walk away with your reputation and hefty deposits on the line. Stiebel recently told one bride: “If you feel you can’t get off this train, I will stop it.”

“People are afraid to call it off, so sometimes they wait until the very last minute,” said event planner Andre Wells. “I always tell brides and grooms, ‘It going to cost you more later.’ ”

Then there’s a less romantic reason — especially if the bride or groom has money. “The pre-nup is always a problem,” said Stiebel. She’s watched couples go down to the wire negotiating the terms of their financial agreement, some signing mere days before the ceremony.

A canceled wedding is hard personally, but usually doesn’t hurt your career. In Campbell’s case, it may have even helped, argues our sports-blogger colleague Cindy Boren: His moment in the news may remind football execs that Campbell is poised to become an unrestricted free agent next month, and that he’s recovered from the broken collarbone that ended his season with the Oakland Raiders.

“This is not my first rodeo,” Campbell said, discussing his career on SiriusXM NFL Radio last month. “I’ve gone through some things. I understand from a business standpoint, things are gonna happen and I’m never surprised or shocked about anything.”

So, a free agent — maybe in more ways than one.

Read earlier: Jason Campbell and fiancee Jenny Montes call off wedding, 2/12/12