The Art of Orgasming Without Orgasming

Every night before I go to bed I like to turn off all the lights and lie on my bed naked. Using a lube I lube my hand close my eyes and stroke myself off for hours. Last night I kept up my routine as usual strokeing my cock with just my lubed fingers and starting from my balls stroking up my shaft and around the head of my cock. I then lube my left hand and use that on my head as I stroke my shaft and balls with my right hand.

Whilst doing this I was fantasising about having a threesome with a girl and a guy imagining me making love to her as I jack him off. After a while my body started twitching and the pleasure was amazing, so much that at one time my back arched off the bed and my toes stiffened. This happened a few times then my pleasure would decrease for a while until it became more intense.

After about an hour I was quite tired so I cleaned the lube off my cock and went to sleep having not ejaculated. This hasn't happened to me before because I always cum after about half an hour to an hour. The fact that the mind does not distinguish between reality and fact is probably why I reached a high level of arousal, the fantasies I was having were very erotic but why didn't I cum? Can anyone answer this for me?