David Arquette: I Thought Courteney Cox Was Having an Affair

David Arquette believed the rumors, too.

In his revealing Thursday interview on The Oprah Winfrey Show -- his first sit-down since leaving rehab last month -- the actor, 39, denied that he cheated on Courteney Cox, but confided that he suspected she had strayed.

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Although the couple announced their separation in September 2010, Cox, 46, began discussing a split months earlier. As the Scream 4 actor has previously revealed, Cox gave him a motorcycle for their eleventh wedding anniversary and, in an ultimatum, said, "I don't want to be your mother anymore."

Shortly after that, Arquette explained to Oprah Winfrey, "She came down really depressed one day, and was like 'I'm really just not happy.'" His reaction?

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"I felt really sort of abandoned at that point," Arquette admitted. "A deal is a deal." (That phrase is engraved on the inside of the couple's wedding bands, which they exchanged in 1999.)

"I was angry with...the dynamic of our relationship," says the star, who has struggled with addiction all his life. " I was angry with my wife."

Further angering him: "There were tabloid stories coming out about her and someone on her show having, you know, an affair."

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When Cox brought up the adultery rumors with him, Arquette says, "I thought she was having an affair with someone. Nobody would've said something like that if she weren't." (He now says he knows those stories weren't "true.")

Also at issue: Cox's huge success on Friends, for which she made $1 million per episode in the final seasons. "She was on this incredibly successful show, so she made more money than me," said Arquette, who added that he sought therapy to cope. "I was sort of always in her shadow. And I'd held all this bitterness."

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Arquette also explained incriminating pictures taken of him with another woman last year. After shooting Scream 4 in summer 2010, the spouses were secretly separated. "There was a period of time there that nobody knew about it," Arquette says. "I would go out and I was available again."

A month into that separation, he said, "I met a girl, there was a waitress at a place...It wasn't [an affair]...[Courteney and I] had an understanding. I was completely faithful."

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Is there a chance for a reconciliation? "I love Courteney," Arquette proclaimed. "I don't know right now. I want us to be the best people we can be, and then if it's together--I want her to be happy, and if me even being the best person I can be doesn't make her happy in a partner--like, who she needs, whatever she's looking for--that's still to be answered."

He added: "I know that I'll be with her for my whole life. And we have an amazing family together and we're really great parents together."

How did Arquette explain his rehab stay to their six-year-old daughter Coco?

"I told her at first I had to go away to a camp, so maybe that part wasn't honest, but it kind of was," he says. When his little girl visited him at rehab, he told her, "I'm here to learn how to be a better person, but I'm also here so that I don't drink anymore because I've been drinking a lot."

Coco, he said, gave a big smile.