There are some serious consequences if you choose not to forgive, and these consequences will significantly affect your future. Harold Graham says when you do not forgive, you become an "angry, cynical, always-assuming-the-worst type of person." He says, "Unless you make that decision to forgive, all that emotional turmoil is going to make you a very unpleasant, lonely person for the rest of your life."
Dr. Myles Munroe talks about how unforgiveness eats away at a person's life. He says, "Unforgiveness destroys your life. You become crippled. You become bitter. You become strapped by hatred and anger. You develop ulcers, and you develop growths and cysts and high blood pressure. All of these things are products of unforgiveness. That's why a lot of people who are still bitter because of broken relationships end up getting sick physically. They have mental problems. They develop an emotional instability. Unforgiveness is a culprit that brings death."
Yes, but forgiveness brings freedom and life. The first thing you need to do, before you take any action or make any kind of plan, is to make the decision to forgive.
"For You, O Lord, are good, and ready to forgive [our trespasses, sending them away, letting them go completely and forever]; and You are abundant in mercy and loving-kindness to all those who call upon You" (Psalm 86:5 AMP, brackets included in original).