Traditionally, the way most people forgive a spouse is to recognize that their spouse is human and not perfect and to at the same time recognize that they are in a co-dependent relationship where they have some responsibility for the problem. They also focus on the future and not the past. They make sure that when their spouse tries to draw them into a fight, that they don't get sucked in by their partner to a negative co-dependent interaction style that the two are most comfortable with.
Then one usually tries to focus on positive aspects of life, finding things that makes one happy, and setting (and enforcing) boundaries with ones spouse so that hurtful interactions are minimized.
John Gottman's book the "seven principals..." has a large section in it on how to interact with a spouse in ways the draw the two of you together as opposed to pushing each other apart. It also has some daily rituals (the 5 or 5.5 Magic Hours each week) that can cement a relationship.
Good luck to you and your family.
>43 years of marriage--My wife and I are now closer than we have been in decades. I believe that my SSM is over.
