Three months ago my wife Rachel had her left kidney removed. It was pulled out through an incision in her abdomen, put on a piece of gauze on an icy tray, rigged up to a drip and inspected by surgeons. Within two hours, it was inside me, doing everything a kidney is supposed to do, as if nothing had happened.

It is still working today and I am starting to look forward to the future for the first time in months. This is the closest thing to a miracle I think I will ever witness.

I had been very nervous seeing her going into theatre. After all, I was the reason she was there. It was because of me that she was being cut open; because of me that she was having a perfectly healthy organ taken away. She was saving my life, just like my brother had done eight years earlier when he, too, had given me one of his kidneys. I'm one hell of a lucky guy.

Only a few months ago I was one of nearly 8,000 people waiting for a transplant in this country. I was fading fast and I knew the statistics weren't on my side. The average wait for a kidney in the UK is three years and hundreds of people die before they can have a transplant.

I'd been in the same position before. My own kidneys had been wiped out by an incurable autoimmune disease years earlier and Tom, my brother, stepped forward as a donor. He was a perfect match and the doctors said his kidney could last 20 years. But after five it began to deteriorate and the symptoms of kidney failure slowly crept back into my life. Tiredness, nausea, itchiness, weight loss, muscle wastage, headaches and anaemia were my bedfellows once more.

By this summer I needed dialysis to stay alive. A tube was punched into my chest and tunnelled under my skin into a vein in my neck. A catheter was on the other end, via which I could be connected to the dialysis machine. It hung rather gruesomely out of my chest, reminding me all the time of the sickness within me, that I was reliant on a machine to survive.

Watching me fall to pieces was horrible for Rachel, and I hated it too. I hated dragging her down with me. I could see that kidney failure had taken over her life as well as mine and that her dreams for our future were slipping away.

When she first suggested being a donor, I was dead against it. The 10-inch scar my brother was left with was not something I was prepared to let her endure. I was told by my consultant at the Royal Free Hospital in London that procedures had moved on. The operation is now done laparoscopically, so incisions are smaller and recovery much quicker.

Even when these concerns were put to rest, I didn't think she would be compatible and I secretly hoped this would put an end to her determination to go through with it. But I lost this line of defence too. The immuno-suppressant drugs that all transplant patients must take are now so advanced that a good match is not absolutely necessary. Rachel wasn't a particularly good match, but she was good enough.

I then had to accept it. Rachel made it clear I had no choice – and as inhuman as it felt to me to let the person I love do this, I also knew it wasn't fair to sentence her to years of waiting on the list as well, waiting for the phone to ring to say there was a kidney, waiting for me to die. It wasn't the life I promised her when we got married and I couldn't deny her the chance to do something about it.

When we got the "good" news that she could be a donor, Rachel's mother offered to do it instead. It was hard enough to comprehend my wife's kidney would be sitting in my abdomen, let alone my mother-in-law's. Squeamishness aside, this really brought home to us not only what Rachel was doing for me, but what her family were too. I'm not sure that I will ever be able to look them in the eyes again.

When the hospital called with a date for surgery, it was only 11 days away. Looking back now, those were perhaps the strangest 11 days of our lives. Unable to really open up about how I felt, my gallows humour took hold. I joked about what would happen if we didn't make it through the surgery and what songs we should have at our funerals. Rachel was not very sympathetic to my choice of 'Should I Stay or Should I Go' by the Clash.

The reality was that I just couldn't bear to think about what was about to happen. I wanted the operation over and done with as soon as possible. Rachel was the opposite – she wanted things to slow down. She gave me ridiculous reasons, such as needing to paint the skirting board in the bathroom before the operation. I don't know who she thought she was kidding – she was obviously scared. And so was I. What if it didn't work? What if we were to go through all this for nothing? The only way I could cope was to put myself in a kind of emotional lockdown until the big day.

Rachel went into theatre before me, leaving a few tense hours before I was out for the count too. The next thing I remember was being told in my semi-conscious state that Rachel was fine and the operation had gone well.

Her kidney got straight to work inside me and on the first day after the operation I produced 12 litres of urine, putting me firmly in Red Rum territory. It may have been the anaesthetic and the morphine, but I felt great. Rachel was fine and there was no need to dig out that list of funeral songs. We would soon be going home to start our new life together. We'd done it.

But two days later something was going wrong. I was bleeding internally and became so sick, I don't really remember much about what happened. I was barely conscious, struggling to breathe because fluid was building up inside me. I knew things weren't going well when my doctors began talking about taking me back into theatre for an emergency operation at midnight on a Sunday. Could there be a worse time to go under the knife? I was so weak, I was frightened I wouldn't make it. After having got so far, it looked as if we might lose everything now.

The surgery was put off until morning, when I was opened up again to remove the blood clot that had formed around the new kidney, but by this point my entire digestive system had gone on strike. The next few days were unremittingly grim. I couldn't eat anything, I had six intravenous lines in my neck, a tube up my nose going into my stomach, a cannula in each wrist and a catheter up you-know-where that went into my bladder.

Throughout it all, Rachel's kidney was still working. Unflappable, strong, loyal – just like its previous owner.

It was another two weeks before I came home, although it hasn't been plain sailing since. I'm on a huge dose of drugs to suppress my immune system. These stop my body from rejecting the kidney but also leave me vulnerable to every bug around. A bout of gastroenteritis put me back in hospital for six days and I've had numerous other infections.

But, bit by bit, I'm literally coming back to life. I have my appetite back and am enjoying the humble pleasures of food for the first time in at least 18 months. I am cooking again – something I used to love. Rachel, for all her strengths, can barely boil an egg, so it's a blessing for us both that I am now back in charge of the kitchen.

I used to wake every day feeling like I had the worst hangover in the world, even though I couldn't touch a drop. That's another humble pleasure I can now enjoy – I had a pint of Guinness the other day and it tasted like nectar. So, too, are simple things like walks in the park on crisp winter afternoons, days out by the sea. Just laughing with Rachel and talking about something other than kidney failure is a huge change. These are the moments when I know it has been worth it.

Last week we got through the crucial three months after the transplant. The chances of my body rejecting the kidney are now very slim, meaning we can sleep a little sounder at night and make some plans for next year.

But every time I see her scars I wince at the thought of what she went through for me. And my brother Tom. Here are two perfectly healthy people who had surgery they didn't need and now have one fewer vital organ, all to help someone else get their life back.

In my time in hospital, I watched several other transplant patients come and go, walking away with a new life. All had received kidneys from living donors. It is incredible that medical science has developed a way to fix people with kidney failure. But is it right to operate and remove organs from healthy people while organs from dead people are buried? If we had a different organ donation system, maybe I wouldn't have to had to put the people closest to me through this.

We don't know how long Rachel's kidney will last. The clock is already ticking and so I owe it to the thousands of others still waiting for transplants to make the most of this gift of life.

Thanks to the amazing transplant team at the Royal Free and the bloody-mindedness of my stubborn wife, I have a future. We've been given a second chance at life. Most men my age hate to see another December roll by, but I, for one, have never been so looking forward to the start of a new year.