So yesterday my fiance's mom decided to ban me from her kid's life. I will not be allowed to see or…

So yesterday my fiance's mom decided to ban me from her kid's life. I will not be allowed to see or speak to my fiance's two younger siblings who I have grown to love oh so much. She even took me off the invite list to watch his little sister promote from the 8th grade! I am so heartbroken and so are they. I just don't get her. I didn't even do anything. All I said was "my loyalty lies with my fiance, but I never want to be put into a situation that would make me have to lie to her." Now all of a sudden I'm a manipulative bitch and making her son pick between us? WTF?!