CLINT EASTWOOD’s furi­ous wife Dina caught the “Dirty Harry” actor cheat­ing and confronted the “other woman” in an angry showdown, The ENQUIRER has learned.

That’s the real story behind the bizarre wife swap situation that’s un­folded among Clint, Dina, her new beau Scott Fisher and HIS ex-wife!

Sources told The ENQUIRER that Dina, 48, caught Clint and Erica Tomlinson Fisher – Scott’s ex – on their way to a room at the Mission Ranch hotel, a romantic getaway Clint owns in Carmel, Calif. The bitter confrontation took place last March, right in front of Dina and Clint’s 16-year-old daughter, Morgan.

“Dina only hooked up with Scott after his estranged wife took up with Clint,” explained a source. “Although Dina and Scott dated in high school, they’d been just friends for years – nothing more. She was a happily married woman.”

The two couples had spent time together when the still-married Scott and Erica were on the mainland visiting family. Scott, a 50-year-old assistant basketball coach at the Uni­versity of Hawaii, and Erica divorced in 2012 after a decade of marriage.

“Erica had always been deeply jealous of Dina,” said the source. “She was obsessed with the lavish life Dina had been living with Clint.”

According to the source, Erica ap­proached Clint in the summer of 2012 under the guise of pitching him a script – and then she turned on the charm. Erica is a “very manipulative, bright and beautiful woman,” said another insider. “Clint was smitten with her and liked the fact that she came on to him so aggressively.”

The insider says Clint, 83, invited 42-year-old Erica to fly with him to his ranch near Shasta, Calif., and he arranged for her to stay with him at his house in L.A.

“Dina knew nothing about this at the time,” added the insider. “It was all done behind her back.”

But in March 2013, Dina got a call from a friend, who said that they had seen Clint and Erica having dinner together. Dina and Morgan raced over to the Mis­sion Ranch restaurant just as Clint and Erica were on their way to a hotel room, according to the source.

“There was a big scene,” said the in­sider. “Dina confronted Erica and said point-blank, ‘I know you’re sleeping with my husband! Don’t deny it! You are a homewrecker.’ Erica lit into Dina, calling her names…then she had the nerve to add, ‘I’m not going to say any­thing else in front of your daughter.’”

Shortly afterward, Clint moved out of the family’s residence in Carmel. In April, Dina entered an Arizona rehab facility, where she was treated for depression and anxiety. Over the summer, Dina stayed at her and Clint’s home in Maui, where she reconnected with Scott.

Dina, who has been married to Clint for 17 years, made her separation from Clint legal on Sept. 9, filing papers in Califor­nia’s Monterey County Superior Court for the legal separation. She is asking for physical custody of Morgan and spousal support. The couple is said to be worth $375 million.

Said the source: “This whole messy thing has been more than Dina can bear.”