Forgiving is not only difficult, it is almost impossible as long as you think that someone is a culprit. But if you see that person, whomsoever you want to forgive, not as a culprit but as a victim of situations, or just a postman to deliver what was due to you, you don’t need to forgive them. They just simply disappear from your domain.
When a postman has delivered you a parcel, that’s it, you don’t think about the postman. You are with the parcel, whether you like it or not. You do whatever you want to do with the parcel. This is exactly the attitude you should have.
When you get a nasty email, you don’t bang or throw your computer or laptop because you’ve got a nasty email. Whatever email came, the laptop just reflects that. That’s all! Similarly, people are just like laptops. You don’t need to forgive them. You simply need to have a better understanding.