In the beginning of a relationship (the rise), you 1) get to know the other person 2) grow to like the other person and 3) develop trust for the other person.
These are simple steps that usually follow in this order. However, when a relationship begins to struggle (the fall - for lack of a better word), these steps are reversed. 1) you begin to lose trust in your partner 2) you grow to dislike things about your partner and 3) you wish you did not know your partner. I hope you never get to steps 2 and 3 of "the fall". Unfortunately, step 1 of "the fall" is very common.
Trust is the last thing to develop in a new relationship yet the first thing to decrease in difficult times.
How have you increased trust in your marriage/relationships?