"Most important of all, continue to show deep love for each other, for love covers a multitude of sins." - 1 Peter 4:8 (New Living Translation)
1) Don't fight back. Humility isn't competitive, pride is though.
2) Forgive immediately or at least start telling God how you feel about it all. He wants you to be honest. I know it's not "conventional teaching" but if you gotta cuss and get angry do it. God wants to get UNgodly emotions out to get His love in. One emotion has to leave (anger) for another (grace) to enter in.
3) Don't go around saying they are terrible. They may have done you a HUGE favor. Jesus was stabbed in the back for OUR GOOD. Without Judas (who we give no credit too) the Cross wouldn't have taken place and saved us. Although of course, God could have aligned other ways but it was all prophetic, even down to the Book of Psalms, hundreds of years before it was all foretold.
4) Write out your hurt. Express your feelings to yourself. Suppressing your feelings only empowers the feelings that are hurting you.
5) Know that something you did was worthy of someones jealousy or anger. Consider that a compliment ;).
6) Pray for the enemy. Jesus said it's proof we are the Fathers sons and daughters in Matthew 5:44-45.
7) Talk to a friend, don't go at it alone. You need someone. You need prayer. You need support. You need Jesus and His healing power, love and wisdom.
8) Don't get cynical! That's what Satan wants. He wants you to distrust EVERYONE because blessings are connected to EVERYONE even the one who betrays you.
9) Some people want in your life to mold you and God says "I am the One who is making him/her Christ-like, not YOU!"
10) Free yourself for yourself. Unforgiveness only makes you a prisoner to them. If you are angry because of the betrayal (though that will be your first response) it isn't the worst part; its the fact they are now CONTROLLING you with their PAST actions, hindering your future blessings, performance and walk with God.
Yes, this is all hard and but this is necessary in the life of ANY believer. If Jesus suffered who are you to think you are gonna get by with a clean slate? Jesus was PERFECT and people hated Him. Sometimes people see your effectiveness and think in ignorance that they aren't doing anything for God. Insecurity breeds competition and competition breeds jealousy, envy, strife, gossip, and ultimately betrayal.
"For wherever there is jealousy (envy) and contention (rivalry and selfish ambition), there will also be confusion (unrest, disharmony, rebellion) and all sorts of evil and vile practices." - James 3:16 (Amplified Bible)
"Make allowance for each other's faults, and forgive anyone who offends you. Remember, the Lord forgave you, so you must forgive others." - Colossians 3:13 (New Living Translation)
Father God in Jesus Name, I come to You and ask You for forgiveness for holding any grudge. Lord, fill my heart with Your Spirit and love. Forgive them. Heal them. Hurt people hurt people. Help me see the good according to Your promise that all things work together for good. Change my perspective and help me to still love them and see Christ in them and pray with and for them. Lord, we love You so we must love others and I ask for spiritual discernment and prophesy as a gift of the Spirit in Jesus Name. Amen.