Problems wih my mother in law?

I am truly having a problem with my mother in law. I have been with my husband since we were 14 years old. We are now 23 with two children. She never talks to me when she calls she will talk to my husband and our children. She came to visit while I was pregnant with our second child and she caused nothing but trouble. She would do things to make my husband think that I was the one starting problems with her and I was doing nothing but kissing @**. I was told by my doctor at the time that he could tell I was very stressed and my blood pressure was elevated which never happened before. I suffered from extreme morning sickness and she threw a fit because my doctor said we should not visit the grand canyon because of my severe morning sickness(I was losing alot of weight from it and thats why he advised).So she manipulated my husband into making the trip anyway. Not just the trip but walking around the grand canyon and I was so sick it was unreal. The one place I wanted to go on that trip we didn't go because she didn't want to. She made the whole month she was here terrible. My husband screamed at me because she would throw little fits about stupid stuff. I swear I did not do anything and my husband now a year later said he realizes that but I am afraid for her to visit again. I am not lying when I say we almost lost our marriage to that trip she made here. She still don't talk to me and I even started to try calling here once a week to kinda get on good terms. I want to have a good relationship with her but she just won't let me. My husbands brother got married and she keeps telling my husband all these nice things about her. I just don't know what to do anymore. She keeps being mean and doing bad things and I just keep going back for more hoping that she will one day stop doing this. My husband never stands up to her and I just feel stuck. Like I stated above I started calling her to kiss her @** even more but she even cut me off today and didn't want anything to do with talking to me. Seriously our conversation was less than 2 minutes. I confronted her about 4 months ago and she says I never did anything so why? Why?Why?Why? She does have bipolar and I am not sure how that would affect something like this but it needs to stop. She does such hurtful things sometimes and you can tell she knows shes doing it. Just like when she gets my husband to yell at me when he should be yelling at her. He has since our sons been born started to see through her but he still won't stand up to her. It sounds crazy but its almost like I need him to for once yell at the right person. We talked awhile ago and I accepted his apology but I just don't feel like everything will be ok until he puts her in her place. Not for what happened over a year ago but for the stuff she does now because I feel like as long as she knows she can do it she will do it. I am going to have my husband read the comments so that maybe we can resolve this so please post with helpful advice. I want to thank all of you in advance for your participation.