When a person is buried in pain, it is extremely difficult to think and control your emotions. The tendency to react rather than decide how to respond is a huge skill to acquire. The person that had the affair often wants to justify their course of action and the betrayed spouse is still in shock. It is this situation which causes the most difficulty in moving forward. Problems are a part of any relationship It is how you deal with problems that is foundational. Infidelity can be worked through but it takes the efforts of both parties to be able to make that happen.