I would start by suggesting on getting a book like Co-Dependent No More by Melody Beattie. It may help you sort out the way your relationship functions and why you and your mother do what you do. Once you learn more about the dynamics of the relationship it may be easier to change your part in it.

Until then I would suggest that you step out of the cycle you have with your mom. If she says something that hurts simply say "Mom, it hurts me when I hear that." Then change the subject. If she won't let you change the subject tell her simply "Mom, I can't talk like this anymore, it hurts me too much." Then hang up the phone or walk out of the house. You don't have to take her verbal abuse.

I also suggest that you do seek a therapist. They are great at giving suggestions on how to deal with difficult people in your life. They understand the causes and affects of these relationships and know the best way to diffuse them.

Good luck!
Carrie

<font color=green>Not knowing when the dawn will come, I open every door.--Emily Dickenson