JESSICA SIMPSON’s long-delayed wedding to Eric Johnson is up in the air again after a series of explosive blowups over his lack of ambition, a baby battle and family infighting, say sources.

The “Dukes of Hazzard” star, 33, is threatening to pull the plug on her impending nuptials after it became clear she and Eric were never going to see eye to eye on a prenuptial agreement that would protect her $150 million fortune and business empire which brings in $1 billion in sales annually. She’s also tired of being the only breadwinner and furious that the former football player – whose last paying gig ended when he was released by the New Orleans Saints in 2008 – doesn’t have a job.

In February, a beaming Jessica excitedly told an interviewer that she and Eric, 34, had finally picked a date. But now the blonde bombshell is singing a different tune.

“In just a matter of weeks, Jessica’s wedding joy turned into a nightmare,” said a source. “She’s fed up with Eric.

“He was talking a big game about opening a vegan restaurant chain, but when Jessica recently asked to see his business plan, Eric just shrugged his shoulders.

“The realization is setting in that Eric is not moving forward. Jessica is ready to cut her losses and move on.”

Meanwhile, the Texas native is at the top of her game. A Weight Watchers spokesperson, she’s dropped from 180 pounds to 110. And she’s one of the fashion industry’s hottest brands with her popular line of shoes, swimwear, perfume and luggage.

Jessica and Eric have been engaged for more than three years and have two children, daughter Maxwell, 2, and 10-month-old son Ace. Eric is ready to add to their family now, but Jessica’s not on the same page.

“Eric wants a total of five kids,” the source explained, “and Jessica is happy right now with two.

“He’s been pestering her about having another baby, but Jessica has her hands way too full right now. Besides, she fought long and hard to get her figure back, and she doesn’t want to throw all that hard work away.”

Eric’s parenting skills also came under fire when Jessica posted a photo of her 6-foot-3 fiance tossing Maxwell high over his head at the beach on April 15, which had Internet posters blasting him as reckless.

The relationship has also been strained by Jessica’s complicated family drama. As The ENQUIRER revealed,  she’s furious with younger sister Ashlee, who she thinks is trying to steal her thunder by racing to the altar with fiance Evan Ross.

“Jessica’s self-confidence is soaring because she’s never looked better and her brand has never been stronger,” the source noted. “Basically, I think Eric is like a weight strapped on her back, dragging her down.”