The Lord God puts people in our lives for a reason.
Whatever that reason is, we need to search Him for answers - not one another. Search His Word - it is faithful and true.
We cannot hold other believers - or even non-believers - responsible for the many feelings that swell up within us when someone or something offends us.
Unforgiveness does not show the love of God. God is love. Therefore, if we walk in the light as he is in the light then the blood of Jesus Christ cleanses us from all sin and we have fellowship one with another. (paraphrase - 1 Jn 1:7)
There is going to be trouble in this world. Relationships are a challenge. But regardless of what has happened, it is so very important not to become bitter. Not to allow the cancer of unforgiveness to enter into our heart, soul, and mind and spew out of our tongues like poison to others' ears and spew out of our actions like soldiers combatting an adversary. Our fellow brothers & sisters in Christ are not adversaries. And those who are non-believers are not our adversaries.
Our enemies are not of flesh and blood.
We are complicated and intricate beings fashioned beautifully by the exact hand of God. All of us - believer or not. We need to learn to forgive and we can only learn by looking to the one who Forgave all of us: God. Through His Son, Jesus Christ - who was obedient to the Father all the way to death.
Let it go. Whatever it is. Lay it before God. He will not forgive you if you do not forgive others.
2 Chronicles 7:14
If my people, which are called by my name, shall humble themselves, and pray, and seek my face, and turn from their wicked ways; then will I hear from heaven, and will forgive their sin, and will heal their land.