Fiona McCade: Hoping for a happy Hollywood ending

When Courteney Cox and David Arquette married, they had their wedding rings engraved with the words: "A deal is a deal." Some people thought this was weird; I liked it. I thought it sounded serious; like they meant it. Turns out that some deals are made to be broken.

Last week, when I heard that Courteney and David were separating, my heart hit my boots. I don't usually care whether celebrities stay together or not (although Brad and Jen, and Susan and Tim's break-ups made me sad). It's not as if Hollywood stars regularly reach their golden weddings, so nobody really expects much from them. But after a scandal-free run of 11 years, I genuinely believed Courteney and David would make the grade.

I've always liked them, and the quiet, tasteful way they lived their life together. They got married just a couple of weeks after me and my beloved, so we were neck and neck in the marriage longevity stakes.

She's beautiful and successful, but she makes and keeps good friends (always the mark of a top person in my book). He was sweet and geeky, and they obviously really loved each other. Then there was that Coke advert where she "shared" the bottle by taking most of it for herself and pouring the last few drops over an awful lot of ice for him. I thought, I can relate to this couple. Then this. Then they gave up. How could they give up?

I've taken this split very personally, I'm afraid. I'm looking across the breakfast table at the man I married, thinking: What would I do if, after all these years of being together, you suddenly went on a shock-jock's radio show and announced we hadn't slept together for months, so you'd had sex with " a girl…once, maybe twice" and that it made you feel "manly"? Then tweet about how "sorry and humbled" you were for making such an arse of yourself? Because that's what David did, just hours after the separation was made public. His excuse is that Courteney told him he can do "whatever you want to do" and that he's "essentially free to see (other] people".

But David, you don't have to do everything Courteney suggests.

Now I remember Courteney hinting at trouble when she told an interviewer: "We have the same arguments we've had for years", but at the time, it didn't seem significant. I just thought, OK, you argue. Don't we all?

I don't want this to happen. I want to rush over to California, bump their heads together and say: "Work it out. You've got to work this out. I had faith in you and now you've let me down. A deal is a deal, don't you remember?"

Perhaps the most telling moment of the past few days came when ol' loose-tongued David let another nugget of information slip: "After our 11th-year anniversary (in June] she gave me a motorcycle and said 'I don't want to be your mother any more'. I got it."

I think we've all got it now, David. She's a grown-up, you're not.She's a sussed and sorted 46-year-old; you're a big baby who's just turned 39 and is obviously embarking on a hideously public mid-life crisis.

This is very bad news, but I'm not giving up. In fact, I'm hoping for a miracle; a miracle that has happened before - to John Lennon and Yoko Ono.

In 1973, after a world-famous love affair and marriage, John and Yoko split up.

She was 40, he was 33. "Mother" (as he nick-named her) told him he could do whatever he wanted and even provided a girlfriend for him to do it with. He went crazy and ran amok in Hollywood, wearing sanitary towels on his head and making an arse of himself. Some 18 months later, he came home. And she was waiting.

I want a similar happy ending for Courteney and David, because they have a little girl, because they've said they still love each other "with all our hearts" and because, for me, they symbolise something that's worth fighting for.

Whatever may happen, a deal is still a deal.