Well the first thing you have to do is to see what you really want. Do you want to leave? Or do you just want your wifes attitude toward you to get better? If you still love you wife and feel like things will be better if she adjust her attitude a bit. Then this can possibly be fixed. First, by being honest with her and letting her know about the way she acts, and how it is driving you away from her. Tell her that you still love her but that the way she behaves is making it very hard for you to want to continue the marriage.
Another thing I suggest in couple's counseling. Counseling can assist her in finding the root of why she is the way she is and how to be more sensitive to other's needs. Since she has no friends, maybe you can encourage her to get into a mother's social group. Or a play group so that she can be around other people....other mothers to me more specific. It is possible that she may get rude with them. But it is also possible that by observing other positive wives and parents, that she may learn a different way to act, and understand what she is doing wrong.
If your wife says she loves you then she more than likely does. The thing is, she is rude to everyone and she just may not know how to express her love. She may also be depressed because she has not friend and does not go anywhere which may make her edgy. In any case, try to have a serious talk with her first, and then counseling before leaving. That will give you a a better decision on what you should do.