When people begin a new relationship, they are naturally isolated from friends and family. This occurs because they are busy spending time getting to know their new partner, and friends and family are aware of the situation. It should only take a few weeks before the person begins to look outward again past their new relationship, and this is when the person they are dating is taken to meet their loved ones.
A person who is intent on isolating their partner will stay with the normal course of events at this time, and they will put forth the effort to meet friends and family. Many times, they will be kind and caring in front of their partner. The problems begin when their partner is busy, and the isolator will begin subtly insulting friends and family. They will leave a less than good impression, but friends and family are generally too stunned to react immediately.
Once a few days have passed, the person being isolated may hear from their loved ones. Their partner has already been making subtle comments about the people they have met, and many of these comments pick away at their personalities and life styles. When friends and family mention they are not sure about the new partner, the person being isolated feels compelled to defend their partner. This causes a rift between them and their loved ones, and it will widen over time.
People who are successful at isolating their partner are often shrewd and manipulative, but this does not necessarily mean they are intelligent. They use this process to get a partner to accept their behavior, and they have no intention of making changes in their life. They need a person who is completely committed to them, and they tend to have socialization or confidence issues. While they might be able to overcome their issues, they would rather isolate a partner than take a chance of losing them.