SOFIA VERGARA’s fiancé, NICK LOEB, wants more than her hand in mar­riage – he wants to control every facet of her life, insiders claim!

That’s what insiders are saying after the 37-year-old entrepre­neur recently went behind the “Modern Family” star’s back and fired members of her sup­port staff. They add that Nick’s also been pressuring Sofia to make questionable investments as well as alienating her from close friends.

“He fired Sofia’s beloved maid a few weeks ago,” a source told The ENQUIRER. “He warned Sofia’s handlers that her manager is on the chopping block too, because Nick wants to push her more into movies and away from TV.

“She has no idea the extent to which Nick is trying to take con­trol of her career and finances. He’s treating Sofia more like a bank cash machine than a bride-to-be. And Sofia is such a loving, trusting woman that she would never suspect that Nick is using her for her fortune.

Nick, the son of a former U.S. ambassa­dor and banking heir, is said to be worth $15 million, while Sofia reportedly earned a whopping $19 million last year alone.

They started dat­ing in 2010, but hit a rough patch last year.

BUT Nick managed to grovel his way back into the Golden Globe winner’s good graces and proposed on July 10, her 40th birth­day, during a romantic makeup vacation in Mexico. As The ENQUIRER reported, she accepted but put in place an iron-clad prenup that would make him pay millions if he should stray again.

Now the two are gearing up for a splashy Mexican beachfront wed­ding which is slated to take place during the Christmas holidays.

“Some of Sofia’s friends think she’s about to make the biggest mis­take of her life,” noted the source. “But Nick has some sick, weird power over her.”

The L.A.-based actress is even considering acceding to Nick’s wishes by making New York City her primary home. In fact, the two were spotted looking at Manhattan apartments on Oct. 27.

“Nick’s a very controlling guy,” added the source.