After betrayal, it is common to feel depressed, angry, unstable, and to have trouble coping in other areas of life. It can be a roller coaster between feelings of hope and then pointlessness; a desire to help the relationship survive and then a desire to end it. It is normal to feel all over the place.
Often sleep troubles follow finding out about infidelity. Thoughts about what has happened in the past and what will happen in the future haunt us. Relaxing seems impossible. Parts of daily life feel unreal and we feel disconnected from others.
There are multiple causes of infidelity.
One possibility is an underlying sexual addiction, often rooted in pornography. Addiction manifests in a loss of control and a change in feelings and behaviors beyond what that person could foresee. A person may see that their behavior is bringing them harm, yet they do not know how to stop.
Another possibility is that a partner engages in infidelity for lack of defenses against being groomed. Grooming is a predatory behavior where someone skillfully learns how to identify what a targeted victim wants or needs and then exploits those desires. A victim of grooming may be feeling distress and anxiety about upsetting the predator and thus continues in infidelity.
A partner may also seek to satisfy unmet relational needs via an affair. When a person feels like their partner is unwilling or unable to meet their needs, they may become attracted to someone that they would not have noticed before. The excitement of mutual attraction mixed with previous pain leads to crossing boundaries.
Infidelity can also be a form of passively ending a relationship. Sometimes a person wants out, but they are not willing to leave, so a dynamic is set up so that you will leave them. It can be divorce via affair.
Lastly, infidelity may be a form of revenge. A person might attempt to inflict the same kind of pain that they have experienced from their partner. They may believe that what they want is more important than the needs of the relationship. Entitlement and revenge lead to breaking commitments with little guilt.
Surviving infidelity requires finding the root cause of the behavior. For this to happen, emotional safety must be facilitated so that both partners can share with rigorous honesty. There is no other way to build a new foundation of trust. Both partners are often anxious to move past the difficult emotions and the thousands of questions about what happened and why. However, the pace of healing is directly proportional to the level of honesty and accountability exhibited by the person who was unfaithful.