Cutting a toxic person out of your life

How many of you have had to do this? I am debating cutting someone out of my life right now, but have hesitated because it will undoubtedly bring a ton of drama and affect relationships with people I actually do want in my life (the persons mother and sister). I hesitate because I have had this person in my life for a long time and at one point felt as if no one could possibly understand me better. It is hard to let go of this and move on but I've realized this person brings me more hurt feelings than good ones.