Everyone has been hurt or betrayed at some point before. The people or person that hurt you could have been a really close friend, a spouse, a boyfriend or a girlfriend. Regardless of who it was it made you feel a certain way and it is ok to feel that way for a little while, but to hold onto that hate, anger or frustration in your heart against that person for what they did is not healthy and is not what the Lord asks us to do. The Lord asks us to love and forgive them just as Jesus did when people betrayed him.
God's grace is so full and renewing. If we truly believe, love and follow God then it is his grace that will allow us to forgive those that have done wrong to us. We will want to be obedient to what he asks of us when it comes to forgiving others because it is not about us and making ourselves look good it is all for the glorification of God. His image and his love will shine through us and those that have done wrong to us will see that and maybe they will look into their own heart and see if they need to change.
Yes I am a Christian and I walk with the Lord in my faith, but that does not mean that I find it easy to forgive people when they have hurt me or to not have hate in my heart against them. Walking with the Lord is not an easy path but I know that my savior Jesus loves me enough and everyone on this earth to have died on the cross for us. When I am reminded of his strong love for me it makes me want to show his love to everyone. In Luke 6:27-28 Jesus says " But to you who are listening I say: Love your enemies, do good to those who hate you, bless those who curse you, pray for those who mistreat you."
It always seems easier to feel the hate towards another person or choose to not forgive them but I strongly encourage you if you are feeling that right now with a friend or a partner because you are fearful of what is going to happen next, but God is not a God who allows fear rather he provides peace in our hearts.