While some people can immediately identify a person with whom they would never be compatible, many suffer from low self-esteem and end up changing their own personalities, wants and actions to fit their partner. It is true that almost any successful relationship requires a certain amount of flexibility and compromise; but if a person is required to alter themselves greatly in order to maintain the relationship often something is wrong. The changes that occur in many of these cases can be so subtle and over such a great length of time, that often the people changing are unaware of how different they have become.
In order to understand how a person can be involved in such a relationship, it is important to remember that many of the people who experience this had a problem before the relationship began:

Insecurity: Many people in our society suffer from one form of insecurity or another; abnormal physical traits; lack of proper education; difficulty with communication and poor support network are just a few of the causes of such feelings. In order to have a strong enough sense of self that a person would never allow themselves to be overhauled by another person they must, for the most part, like who they are. The image that many people have of themselves is a very poor one and this makes it easy for others to prey upon their weakness. Unfortunately, in many cases, the addition of a stronger partner allows the more insecure person to hang all of their self esteem on the fact that their partner would have them; this is not a healthy way to depend on another person for support and in most cases will lead to disaster as it does not usually help to create strength and confidence.

Psychological Damage: A problem that often stems from an abusive relationship, a damaged psyche makes for an excellent weakness for others to prey on. We have heard this referenced many times in society by referring to the ugly duckling syndrome i.e. a person who once thought of them self as unattractive and became so used to dealing with this poor self image that when they became more attractive, by society’s standards, they did not act in the normal way an attractive person would. This by many people’s definition is an attractive person who retains a poor self image; therefore the person will have lower standards when it comes to dating. Many different types of trauma can cause a person to feel unworthy of attention and react in an unhealthy way when it received; this makes a perfect breeding ground for people who are looking for a person that they can control in a relationship; because they lack the self esteem to refuse.