Forgiveness is a tricky thing - many times you feel like you have forgiven someone but then they go ahead and do something and your resentment starts over all again showing you that you have not really forgiven them.
Rather than focusing on forgiving the other person, I find that it is easier to focus on your own healing from the hurt they caused you. When you heal, the forgiveness automatically follows. There is a saying that "resentment is like holding burning coal in your hand. The only person that gets hurt is you". So, at some point as you heal you forgive them because you are no longer angry and resentful. This is not because you are forgiving them for their sake but because you have moved on from them and they don't hold the power over you to hurt you anymore.
