"However, I have missed out on both of those goals.''
Dean said the last year had been tough on both him and his family.
"I have had to think hard, and that I have been doing a lot of. When do sheer guts and determination and pride succumb to hopelessness? When is enough, enough?
"At times during the last few weeks, my effort to make a rapid return to full recovery has had me swinging on the edges of sanity, with Carole and the boys paying for it, as loved ones most often do.
"In fact, my athlete behaviour has, even at times, been destructive to my rehabilitation, as I often seemed to have lost sight of the fact that there always won't be a steady rate of improvement.''
Dean broke his leg in March while riding for fledgling Australia-based team GreenEdge, Dean crashed into a parked car swerving to avoid a multi-rider pile-up during the third stage of the Volta Ciclista Catalunya.
Although Dean had decided to withdraw from Olympic contention he was still determined to continue to ride professionally.
"So now it seems almost like I am left with nothing to do or shoot for, and in a sense it is almost right and it has made me think about hanging it up.
"But it just doesn't seem the right thing to do for any of us at the moment.''
A professional rider of 16 years and about 20 Grand Tours, Dean said it had been a difficult decision but he had accepted it and was now focused on his recuperation.
"Since being faced with the reality of not competing at the Tour and now the Olympics, I have retreated to the mountains to my favourite place for riding a bike.
"It has given me a chance to take stock of things and although lately I began to question my passion and commitment _ due mostly to my unrealistic expectations _ it has become clear to me that my absence at both these events won't be through lack of desire or effort,'' Dean said.
"I tried to set myself probably the most difficult task, and with maybe some of the greatest expectations, I have ever set myself in my career.
"So now with the pressure off of getting to either event, I have time to breathe a little and take a more relaxed approach, which I am sure those closest to me are also happy _ or relieved _ about.''
Dean posted he would continue his training programme to prepare for the Tour of Poland in August.