"When you find out she has a new lover you want to end it all."

It's not like being punched in the guts or being winded. It's like a vacuum cleaner has been plugged into your body and sucked you clean of all the intangible things that went into making you the man you once were.

The marrow of life – all the emotions, feelings, experiences, memories and thoughts that made you a happy individual – gone. You may be able to walk down the street, you may look like the same guy to your family and friends, but you no longer really exist. You are a facsimile of a human being. A mannequin. The only thing that now defines you is that you are one of "them": a statistic. Just another fool who thought you'd bought happiness for the rest of your life by falling in love and walking down the aisle. But, in reality, you've opened yourself up to ending your days in heartache.

Nothing prepares you for it. You might see the signs, but you never expect it to actually happen. You go over in your head a million times what it might mean when she says, "I love you, but I'm not in love with you", but it doesn't really matter. In getting to that point it's over. There are no Hollywood endings with dead marriages. You resist accepting that brutal truth, of course. Nothing is final. You cling to hope. You seek the counsel of people you trust. You fight for her. You plead. You try to do all the things that you should have done when you were still together: get fitter; dress better; be emotionally available; offer to do whatever you can to reconcile. But she's made her decision. For her, there's no going back.

Yet for you, there's no way forward. You’re stuck in a cycle of projection and self-recrimination. You can't understand why she doesn't want you when others do. You use women for sex. You get high on drugs. You get wasted on alcohol. You punish treadmills at the gym like you're training for an Olympic marathon. You do anything you can to begin to backfill the incredible pit of emptiness, but nothing gives you comfort.

When you find out she has a new lover you want to end it all. How can she replace you so quickly? You confront her. You confront him. They don't care about your pain. They're in love and rubbing their happiness in your face. You have nothing to say that's going to change anything, so you do what most stupid males do and start making life difficult for her.

You delay answering her texts. You barely acknowledge her when you call to say goodnight to your child. You quibble over money. She doesn't love you so she might as well hate you. You don't give a damn anymore. You're going to find a better woman and forget she ever existed. You go to bars. You surf dating sites. You smile at girls on the beach. You wax your chest. You get your eyebrows shaped. You "move on" with your life. People remark on how well you look.

But in the still of the night she haunts you. You see her in your dreams, which unspool in your mind like grainy, sun-drenched super 8 movies of summer holidays past. Back when the going was good. You wish just one of the hundred girls who pass through your bed like a fairground turnstile could be her. Just once. None of them look as good to you as she does. Yet she never comes. She's lost to you. And there's nothing you can say or do that is ever going to get her back.

Your only ally, of course, is time.

All wounds heal; that is a crock. You'll go on getting hurt even when you think you're well and truly over her. And the two of you cannot truly be friends, even though that's what she wants and what you realise is the most realistic outcome for everyone. But you can try being friendly. The alternative is stark.

Then, eventually, miraculously, the pain lessens. You accept your solitude. You even come to enjoy it. You won't ever forget the abandonment or the rejection. That sharp jab you get from seeing her with another man will always be yours to bear, no matter who he is or how nice he is to you – even if you marry again. They are horrible sensations you may take with you to your grave. But you come around to forgiveness and tolerance. You finally get some clarity on your own mistakes and the impossibility of finding perfection.

The marrow that was drawn from your body returns. You become a functioning human being again, capable of giving love to others and even loving yourself. Without realising it, you have prevailed over one of the most traumatic events life can throw at you. And you've become a better man for it. Damaged perhaps. Lumped with some baggage. Not the man you used to be. But better. Happy to be alive. And hopeful for brighter days.