I totally understand. My step-mom is a controlling, narcissistic bitch. She's completely ruined my relationship with my dad (he used to be my best friend).
At Christmas this year she said out loud (at my dad's parents house) that my brother and I don't matter and that we don't deserve to see our Dad; and that her kids are the only ones that matter to them. My dad literally just sat there and did nothing, looking down at the floor.
We (me, my brother, hubby and my daughter) left and I snuck back over later so my dad could play with my daughter for a few minutes while she was taking her youngest son home (who is a 35 year old creepy sex offender, and is her "pride and joy").
Some people are just nasty. Don't let the hate in. Live your life to the fullest.