The way to truly and honestly forgive a person is to pray for them. It's a simple concept but because of all the memories, experiences, and emotions towards that person, it's the hardest thing to do.
You know how hard it is to pray for someone that you absolutely cannot stand in real life. You know how hard it is to be in prayer and have to say their name out loud and tell God that you forgive them. Just having the conversation in prayer is difficult on its own, but sis, to have to pray Lord bless him and give him great things and a great future and have your hand on his life, now that's a whole 'nother level of difficulty. It's also a whole 'nother level of maturity.
You may be reading this thinking that this task is easy, you may even think I'm going to go pray right now and list everyone that hurt me so that I can forgive them and move on. But please know that once you start speaking out loud the emotions and memories are going to flood back.
This may make you want to change your prayer to God get them and hurt them like they hurt me. Kill them, hit him with a car, make him lose his job because you know what will really hurt him is to be broke. And God you know he loves that car so take that too, because he needs to pay for the pain he caused me.
But sis, that's not forgiveness, that's more like anger and bitterness. We all want our exes to hurt in the same way that we are hurt or to hurt more than they hurt us. But who hurts the most is you, the person that hurt you is living their lives, the only one being held back from this situation is you.
Not forgiving someone or even holding a grudge for years down the road can lead to pains in your body, high blood pressure, migraines, unanswered prayers. Don't be so stubborn that you'd rather hold up your life because of something you went through years ago.
If you are ready to move on and no longer be held back by the situations or the people that you encountered along your journey; forgive him.
Simply just say "God, I forgive _____ for _____" no it's not going to be comfortable at the beginning and it's ok if you drop tears but it has to be done. And it's also ok if you have to do this more than once, depending on the pain that was caused you may have to say it more than 10 times. Do it until it's comfortable for you to say it so that you can get the healing you deserve.
Once you are actually healed you will be able to meaningfully pray that they received healing, that God bless them, that God gives them their hearts desires, renew their minds. In return, you will not only be blessed for forgiving them but the weight of your past will lift off of you.
Like I said in the beginning, a simple concept that can be the hardest thing to do, however, it is mandatory if you want to live your best life.
Forgive him sis!