I find two things very encouraging about your letter: one is that you recognize you have a problem with compulsive lying, the other is you want help with it. There are some people who lie and have no desire to change. For them, lying is a way of life. It is something they do on purpose because they are trying to project a certain image. With few exceptions, many of those individuals are not able to be helped. Usually that is because they have no desire to be helped. They would not want to see a therapist, and feel that they have no reason to change. That is not the case with you. You want help. You want to change. You don’t like how the lying has negatively impacted your life and the lives of others. You have lived with its consequences and you are tired of it. It is a burden for you, not something that you use to further yourself in life. From my perspective, there is hope for you.
You say that you cannot stop lying. You may not be able to help yourself but a therapist could. The therapist could also help you with the other issues you are experiencing such as your extreme mood swings and your marital problems. Borderline personality disorder is treatable but it requires hard work and a dedication to improving your life.
One interesting aspect of your letter is that you feel as though you are “split in half.” Some research has shown that individuals who have difficulty with compulsive lying have described a similar feeling. The good news about the research is that it shows that lying is a problem that can be dealt with in therapy. That is very encouraging.
Here’s a link to a website where you may be able to find a therapist in your community. I hope that you will strongly consider therapy because it can help you. You are worried that a doctor will not believe that you have borderline personality disorder. That fear may be unrealistic. What matters most is that you find mental health professionals who are able to help you solve the problems in your life. The first step is making the call for an appointment. That should be your next step. I wish you well and hope that you are able to find the help you need and deserve. Thanks for writing.