THE tension between ANTONIO BANDERAS and MELANIE GRIFFITH is nearing a crisis point over fears that he’s cheating – and pals say the Hol­lywood power couple is now on the brink of a $50 million divorce!

And while Melanie was the bigger star when the A-listers married 16 years ago, sources say Antonio could walk away with half their fortune AND wind up ahead because his earning power has soared while Melanie’s has plummeted.

“There’s a lot of money at stake,” a family friend told The ENQUIRER. “Melanie’s a mess. Not only is she in jeopardy of losing the love of her life, but her career is in the toilet while Anto­nio’s star is continuing to rise.”

As The ENQUIRER reported in our June 18 issue, the long union reached a breaking point after his reported flirtations with TWO gorgeous, exotic beau­ties at the recent Cannes film festival in France.

“I think Melanie’s self-esteem hit an all-time low and she believed Antonio was torturing her,” the friend continued. “For years, it is as if she’s been consumed with jealousy over his flirting and outspoken love for beautiful women.

“I don’t think Melanie can live with the constant fear that he might cheat.”

Melanie, 54 – who has a 15-year-old daughter, Stella, with Antonio – blew up after seeing photos of the “Zorro” hunk getting overly cozy with two beauties in France, says a source. Making mat­ters worse, just a few months earlier, Antonio, 51, was caught getting VERY friendly with a young Melanie look-alike at a Cancun nightclub.

Adding fuel to the fire is the huge im­balance in their career status, notes an insider.

“When Antonio and Melanie first married, she was the bigger star,” the friend explained. “But she hasn’t done a ma­jor film in years, while Antonio has gone on to international stardom.”

He is reportedly worth $30 million, while her fortune is estimated at $20 million.

Melanie has already been divorced three times – twice from former “Mi­ami Vice” star Don Johnson. The second time, she bolted from their home in Aspen with their then-4-year-old daughter Dakota while heartbroken Don entered rehab in a futile attempt to save the marriage. And her union to “Scarface” actor Steven Bauer crashed and burned among accusations of his cheating.

“Melanie’s a dirty divorce veteran,” said the source. “But a split from Antonio could very well be the nastiest. There’s a lot of money at stake – and a lot of emotion.”