|“|| Sam: I thought it was supposed to be this perfect fantasy.|
Dean: It wasn't. It was just a wish. I wished for Mom to live. Mom never died, we never went hunting and you and me just never... ya know.
— Sam and Dean
in What Is And What Should Never Be
It is an important point that this is not Dean's view of how he wants his life to be, but rather a construct of his subconscious formed from the one wish - that his mother had never died.
In the fantasy universe, Dean has a girlfriend called Carmen Porter, who is based on a model from a beer ad. Sam is at college, and engaged to Jessica; he and Dean are not close. Mary still lives in the family home, but John died the previous year. (What Is And What Should Never Be)