MEL GIBSON and KELSEY GRAMMER may have struck out at mar­riage, but their ex-wives scored BIG in their divorces!

Both Robyn Gibson and Camille Gram­mer were publicly humiliated by their former husbands’ cheating ways, but the sting of infidelity has been made a little less painful thanks to their multimillion-dollar divorce settlements.

Robyn and Mel wed in Australia in 1980 and had seven kids. But after three decades together, Robyn had grown tired of her husband’s boozing and womaniz­ing. Although they split in 2006, it wasn’t until three years later, when Robyn learned about Mel’s romance with then 29-year-old Russian singer Oksana Grig­orieva, that she finally filed for divorce.

Lucky for Robyn, there was no  prenup – and the Oscar-winning actor and director was forced to shell out half of his $850 million fortune!

“You’d think that someone as wealthy as Mel wouldn’t bat an eye at having to hand over half of everything he owns to Robyn, especially after the years of hell he put her through with his skirt chasing, drink­ing and nasty temper tantrums,” a source pointed out. “But he’s furious about it.”

Not only did Robyn walk away with $425 million, she’s also entitled to a huge chunk of his retirement, say sources. That includes half of any film residuals Mel earns for the rest of his life, large chunks of his pension benefits with the Screen  Actors Guild and the Directors Guild of America, and half of the 401(k) benefits amassed through their production com­pany, Icon.

“Mel should count his lucky stars, though,” continued the source, “be­cause Robyn could have been spiteful and pushed for even more than she was awarded.”

While Camille Grammer’s payout won’t be quite as big as Robyn’s, she’ll still be set for life.

The bitter breakup of her 13-year union with former “Frasier” star Kelsey played out in front of a national audi­ence in 2010.

She was a cast member on “The Real Housewives of Beverly Hills” when Kelsey admitted he’d fallen for blonde Kayte Walsh, a Virgin Atlantic Airways flight attendant who’s nearly 30 years his junior.

Although their divorce was final in February 2011, they’re still working out their financial settlement. Insiders say Camille can expect a $30 million payday. “Kelsey and Camille’s assets are estimated to be around $60 million – and Camille is expected to walk away with half,” a source close to the couple revealed.

Most of their joint assets are tied up in three homes they own together, which are cur­rently on the market.

“When their real estate hold­ings finally sell, Kelsey and Camille will divvy up the money and go their separate ways once and for all,” added the source.

“Kelsey doesn’t want to give Camille more than he has to, but he’s so happy and content with Kayte that he’s not sweat­ing the money that much.”