Media playback is unsupported on your device Media caption Alex did not concentrate on any negative thoughts

Diagnosed at 17 with bone cancer, Alex Lewis underwent intensive treatment but knew he wanted to cram as much life as possible into the time he had left. In three years he experienced what some people take a lifetime to achieve, including meeting and marrying the love of his life. He died shortly after his 22nd birthday.

Alex Lewis had been suffering from pain in his arm for several months.

He played a lot of tennis and football, so it was easy to imagine he had pulled some muscles. But the pain did not go away.

By the time he was diagnosed, the cancer had already spread to his lungs. He underwent intense chemotherapy and then a bone in his arm was replaced with a metal prosthesis. Despite further surgery and radiotherapy the tumours continued to spread.

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As he started to confront the prospect of dying, Alex vowed to live each day with as much zest and energy as he could muster. He didn't want his life to be defined by his illness.

"It makes you realise just how precious life is. Life is actually amazing, but to make the most of every minute you do have to look at everything in a positive way," Alex said.

Alex went on a slew of the kind of adventures that many people might spread over a lifetime as rare thrills and treats. He went parachute jumping in New Zealand, dune buggy riding in Dubai and cliff diving in Cornwall. He took a spur of the moment trip to Australia, booking tickets just two days before he travelled to meet friends there for beach parties.

In between trips he endured further treatments, but rarely did that smile leave his face. Alex was an optimist and was determined to squeeze the most out of life.

"I'm having almost the time of my life in a way," he said. "I mean, imagine if you could feel like I do now, but just for your whole life - that would be incredible because you'd make the most of everything. You'd feel like I'm not wasting time."

'Random kiss'

Alex had a strong network of friends and would be the main instigator of parties and get togethers, zipping around every weekend to visit friends in his new sports car.

It was in his last year of life that he drove to a party in Swansea and met Ali Strain, a girl he had last seen on holiday in Australia, and fell instantly in love.

Image caption Ali gave Alex a whole new lease of life

"It was a bit of a random kiss, it just came out of nowhere... and after that, everything went very quickly," Alex said.

"I was thinking that this is the girl I want to spend the rest of my life with."

Ali fell in love with Alex's charming nature . "I couldn't seem to say no to that face," she said, when Alex proposed to her three months later.

They became engaged and Ali moved in to the family home in Oxfordshire to be with Alex. The mutual support and tenderness they offered each other was both heart-warming and heart-breaking to witness.

Andy Lewis, Alex's father, said his son's relationship had "given him a whole new lease of life and he just walks with a smile on his face when he's not in pain".

She is the most beautiful girl in the world to me and I'm going to fight for everything, and it just gives me another thing to fight for Alex Lewis

Alex and Ali were inseparable. "It's still a bit of a dream... and when you're on morphine you are just checking all the time that this is actually happening, because it's all been perfect," said Alex. Ali understood the nature of Alex's illness, but didn't feel the need to dwell on it.

Although physically Alex was getting worse, he loved having someone to share his life with, describing his time with Ali as a six-year relationship that had been speeded up and put into about three months.

"She is the most beautiful girl in the world to me and I'm going to fight for everything, and it just gives me another thing to fight for," said Alex.

By autumn last year, Alex was taking so much morphine to control his pain, it was a wonder he could even stay awake, but he was determined to keep on partying and seeing his friends every weekend. He did his best to ignore how hard it was to breathe as the tumours spread further into his lungs.

'Happy times'

Ali would constantly support him. "He was in so much pain, so I just kept saying 'remember all the happy times... think about the night we got together in Swansea and think about all your lovely friends,' and that really helped him."

Image caption Before he died Alex told his family how incredible his life had been

Over the course of four years Angela, his mother, had been with him throughout every hospital stay and treatment and by now had learnt a lot about the illness and pain control.

Alex's family celebrated three Christmases as his last.

In February 2011, the wedding was rushed forward. But after the marriage, Alex deteriorated quite quickly and sadly passed away.

Despite all the hardships and pain Alex endured - his joyous attitude was infectious and seeped into the consciousness of those around him. He was far more worried about the impact of his declining health on others than he was about his own uncertain future.

He made sure his family and friends knew that he felt good about his life to prevent them dwelling too much on his fate. He wanted to highlight the difficulty of diagnosing bone cancer, because he didn't want other teenagers to suffer what he had been through.

Shortly before he died he told his family how incredible his life had been and how he felt like he had a complete life even though it had been cut short.

Alex's outlook is something we can all learn from. There's still plenty of laughter in the Lewis household. Alex wouldn't want it any other way.