PRODUCTION of “Grindhouse,” the much-hyped Quentin Tarantino-Robert Rodriguez movie opening Friday, ground to a halt last year when Rodriguez fell for his leading lady, Rose McGowan, and his wife found out.Rodriguez and his spouse of 16 years, Elizabeth Avellan, raised five kids and worked together, with Elizabeth serving as his co-producer on “Grindhouse,” “Sin City,” “From Dusk Till Dawn,” “Desperado” and “Spy Kids.”

But the marriage exploded last April when Page Six reported that Rodriguez, 38, had begun a torrid romance with McGowan, the raven-haired, French-Irish minx once engaged to shock rocker Marilyn Manson and previously linked with Kip Pardue, Ahmet Zappa and Men’s Health stud Dave Zinczenko.

“It was the worst-kept secret on the set. They were going off to his trailer, having meals together,” our source said. “Rose thought some of the crew were treating her differently, and the attitude was, like, well what do you expect when you’re [bleeping] the director?”

In “Grindhouse,” Rodriguez’s homage to the cheesy sex-and-violence movies of the 1970s, McGowan plays a stripper who loses her leg and replaces it with a machine gun to battle flesh-eating zombies.

She and Rodriguez first met at Cannes in 2005. But until now the consequences of their shenanigans weren’t fully known. When the director “fell in love with his femme-fatale star . . . he broke up his marriage of 16 years . . . The production had to shut down for a month while he recovered,” Variety reports.

A source told Page Six, “When Elizabeth found out, there was an eruption of emotions – an emotional volcano.”

A Dimension Films spokeswoman would only comment: “The hiatus had nothing to do with Robert’s personal life.”

In the meantime, Rodriguez and McGowan are keeping an ultra-low profile. “They arrived in the same limo for the L.A. premiere, but they got out separately several minutes apart to avoid being seen together,” a spy told Page Six.

Rodriguez and Avellan insist that their separation is amicable and that they plan to raise their four boys, Rebel, Rocket, Rogue and Racer, and daughter, Rhiannon, together and continue their partnership in Troublemaker Studios.

What do you think of her dress?

Rose McGowan feared she’d be scarred for life by a recent freak car accident that left her with a deep cut to her face. The actress was the passenger in a car that was struck by another vehicle. The impact pushed her glasses into her face, slicing into the skin beneath her eye.

She was forced to undergo plastic surgery to erase the resulting scar. McGowan tells PageSix.com, “I didn’t realize I was hurt until I put my hand to my face and felt the flap of skin. My glasses had sliced me under my eye.”