Why can't Montag communicate with Mildred?

Why can't Montag and Mildred remember how they met? The fact that a married couple who has been together for ten years can't remember when or where they met shows the indifference to the past and to relationships that most people in the Fahrenheit 451 society have.

yes they most likly are and have planed t try to bring human life and supplies there also(due to global warming and other harmful resorces)