Disapproving Mother

So to get the full detail on my discussion, I am a lesbian and have been with my partner for four years. When we got together she already had 2 children, a daughter that was 2 and a son that was 4 months. Now the kids are 6 and 4, and I love them with all my heart and consider them to be my children as well. Her family is very accepting of us and so is my father, my mother and my sister are the two that don't really accept it at all. My mother and I have not always had the greatest of relationships. After 4 years she still has not met my partner and has no interest in ever meeting her, but she has met the kids and has been around them for the four years. She is not accepting that I am gay and just wishes that I would meet a nice man, get married, and have kids that way. She doesn't want me to come to her house unless I am by myself. I am pretty certain that if I were straight and were with a guy that had kids she would have no problem with it considering she accepts my sister's fiance with arms wide open. I hate that because of how she feels I don't go over there, which means I don't get to spend much time with my dad, with whom I have a wonderful relationship. I just don't know what to do about it anymore because no matter what I say to her it ends up in a huge argument and us not speaking for months at a time. I would hate to cut her out of my life for the simple fact that it would cut my father out of my life as well.