I knew a guy who was in a relationship with his girlfriend for 5 long years. He got her pregnant in the 6th yr, so he had to marry her. 4 years later, they are divorced. He admitted that he never wanted to marry her, he just settled for her. So why didn't you just break up with her and find a better fit somewhere else?
I also knew another girl who dated a guy for 9 years. Marriage never came accross their minds. Then one day, she told her boyfriend that she was going to move back to CA where her family was from. Then that was how it ended. Apparently she never saw a future with him. But stayed with him for 9 long years.