Sisters no more? When do you cut ties, or do you keep going out of obligation

My husband and I have been married for 10 years and together for 14. We have been actively TTC for 3 years now. On the surface, everything is perfect. I honestly feel like this has been my downfall in other relationships. Because my life appears so perfect no one knows of our fertility issues. Especially my sisters who have always seen me as their competition since we were younger. I have always been the golden child with the straight A's got married first, became a doctor etc so the jealously and bullying has gone on for years. So here is the issue, when my husband and I announced we were going to renew our vows, both sisters rushed to "steal my shine" (yeah they actually said that) by having a baby at my event. My second oldest sister got pregnant and found out a few months after our event (both sisters managed to find other ways to distract from our event though).

When my sister found out she was pregnant she immediately told everyone except me. She made a point to tell everyone she did something before me and that I "better get in line" She then proceeded to pick a fight with me out of no where and say I told her business, then I hurt her feelings 1 year ago at thanksgiving, etc when in fact I did not. This stupid fight lasted for months (as they always do with her) and honestly I believe its because she never wanted me around her child's life and instead of saying it tried to find a reason to not include me. This fight grew to the point of no return when she decided that she will name her baby the name my husband and I chose for our first son after someone revealed to her what our choice would be. When I confronted her about it, she attacked my fertility and told me I will never have children so it doesnt matter what name she chooses, "I just need to decide if I'm going to be an aunt or not" After weeks of this fight lingering, she promised to choose something else and life moved on. I still had reservations about the whole thing because she did not seem sincere. Mind you, she doesnt know about our fertility struggle. Well here is the issue, she gave birth on Wednesday 2 months early. Everyone is excited in the family and then its revealed that she did in fact use the name we wanted. I feel betrayed because she accepted gifts from me knowing she was going to stab me in the back. Then she lied to everyone and said the name was something else and my mother is the one who told me the truth. My other sister makes jokes about me being upset about it and plays both sides of the fence in my opinion. looking at the history between us, I feel like its best to cut ties with both sisters. TTC is already stressful by itself, I don't want my stress and emotions being all over the place because I'm either fighting them or waiting for the next fight to happen. I can no longer take the competitive jealously and it seems like it gets worse over the years. Any advice or comments from anyone TTC dealing with family