It's a cycle that many people experience through this day and age. I guess all I can say is you can find the satisfaction of deleting someone from your Facebook but you can't delete the memories you shared with that person because they were once something to you and you know it.
My advice is, don't give up on the friendships you have that you know that are true to you. You could lose valuable people over grudges and situations that could've been fixed properly or by simply just losing touch and drifting apart.
Otherwise, don't make promises you can't keep. Don't abuse someone's trust if you know you're going to use them in the end. Don't be a doormat to people that don't give a shit about you. Lastly, if you have friends that forgive you for your mistakes, never let them go because it's fucking hard to find those sorts of people anywhere.
