Letting go of something toxic from the past is part of growing up and putting yourself first. It's about knowing how valuable you are and knowing that there is not one person or situation that can change that unless you allow them to. You have so much power over your happiness; you get to forgive and then walk away. It's all good for your mental health!
Forgiveness isn't what you grant someone to tell them you're okay with how wrong they treated you, it's what you do for yourself to prove that you learned something from a bad experience. It closes and locks a door so that you won't go back. Forgiveness proves how smart and in control you are of your future, and it allows you to grow and move forward. It gives you strength to walk away when something or someone is too harmful to keep around.
There are certain points in life that cause you to change who you are for the better. You see the world in different lights and constantly grow from that until you reach the point where you're the most yourself you'll ever be. Who you're around is going to change how you interpret life and become who you're meant to be. You should have people around who have a positive effect on that.
When you're trying to grow and live through hard or important times in your life, you don't need anyone dragging you down, no matter who they are. People have to know that being in your life is a privilege and that being related to you or knowing you for a long time doesn't mean they automatically earn a spot. They don't get to treat you poorly and then stick around for when times are good.
Cutting people out is hard when you have connections and you're afraid to make new ones, but you shouldn't be afraid to let the past be just because you're comfortable; that just means you're too okay with getting hurt. It doesn't matter how close you were to a person or who they were before they broke you. In time, true colors come out. You shouldn't allow yourself to get used to toxic relationships.
There is nothing wrong with closing out people you really cared about, it is not a sign of weakness and it doesn't make you a quitter. It means you are aware of your needs. There's a time and a place for everything and sometimes people just don't have a place with you. It's better than holding grudges and feeling resentment for keeping someone toxic around.
When people exit, you will feel accomplished and like a weight was taken off your shoulders. You'll have room to bring more people in your life to have a positive effect on it.
Growing into who you are and what makes you your happiest will be so much easier with the right people around.