So, why is it so hard to forgive this people who hurt us?
To answer that, I believe the most common reason why people have a hard time forgiving others who hurt them is because they don't understand how forgiven they are.
Why should we forgive then?
1) Because God has forgiven us.
Forgiven us from what?
He forgave us despite us hurting him, rejecting him, being unfaithful, offending him, and more. We owed God a debt we cannot pay, and He gave us mercy. On top of all that, He gave us His Son to pay for our sins and to show us His love. (John 3:16) We were sentenced to death, but Jesus took all our sins and suffered in our place.
"Does anybody here really think that a person on earth has done anything worse to you than what you've done to God?" - Joyce Meyer ("Do Yourself a Favor and Forgive" video)
2) It "chokes" the soul terribly.
"Forgiveness is a gift you give yourself."
I know it's not always easy to forgive, but when we understand how God has forgiven us and loved us despite us being arrogant, prideful, selfish, self-centered, ungrateful, and more, we'll be able to forgive.
I've also experienced people hurting me deeply and the only thing I can do is turn to God every time they do. One person in my life who hurt me deeply is a close friend of mine who betrayed me twice after doing the same thing twice (and despite me giving out all my efforts for that person) in a span of around two years. I still chose to forgave in the end though, but made sure that I'll not trust that person again. Another person who hurt me deeply is my own mom. But God really worked drastically in our lives which included me forgiving her despite everything.. If you want the full story click here. After everything that happened, there was a sense of peace and joy in my heart that I couldn't describe. GOD WORKED EVERYTHING OUT and I believe He will continue to do so.
"Do yourself a favor, and FORGIVE." - Joyce Meyer