We all tend to grasp tighter onto people the longer we know them. Personally, I formed a one way bond with someone who never even considered me a close friend. I gave this person a ton of importance because we have known each other and were considered "best friends" for much of our childhood. And as more and more years passed, I thought we were closer and closer. That was not the case, however.
Especially after we came to college and were part of the same new friend group, I started to notice how fake she was. How she would smile to my face but complain about how annoying I was behind my back. I kept giving her chances because of how long we've known each other — 11 years — but she kept doing things that a real friend would not have done.
This behavior is toxic. Keeping people who aren't loyal to you around you is toxic. Continuously forgiving them is toxic. These habits lead to feelings of sadness, loneliness, and lowers self-confidence, as well. If you relate to my example above, please reevaluate your friendships.
It is way harder said than done, trust me I know, but you must get rid to these people from your life. It will take time; start with physically creating more distance between you and the person. Not being around this constant negativity will show you how happy and successful you are without them, and this will make it easier to mentally and emotionally let go of them. This process may cause your relationships with others to change, as well, but see it in a good light because the others who also distance themselves from you were never truly your friends in the first place. If they can't love you for doing what is necessary to be happier, then they don't deserve to even be in your life or have any of your time and attention.
Letting go of toxic relationships is really hard. But trust me, it needs to be done to live a healthier and happier life.