Each case has a unique mix of causes or motives.

Some may be running away from uncomfortable feelings such as low self esteem, fear of emotional intimacy, need for external validation, trauma, problems with expression of emotional needs, or sexual dissatisfaction.

Others may seek change (running to something) – a temporary escape from the familiarity of the person they have become (one of routine and responsibilities) from the former self and romance that existed earlier in their relationship. The intensity of feeling attention in a new relationship can be intoxicating. A new connection may be emotionally fulfilling by rediscovering a lost part of oneself rather than attaining a better partner.

And some may be content yet vulnerable to an unexpected opportunity for validation.

The question to be asked is what is happening in each party’s life that led to structural compromise of the relationship.