The following comments do not refer to types of things like minor misunderstandings. Rather, they refer to ABUSE, which is a "pattern of sin".
Many of us have been told that forgiveness was similar to overlooking the abuse (i.e. pretending it didn't happen) and entrusting ourselves to that person again. This teaching was wrong.
Regarding the "overlooking sin" part:
God does not make light of what people have done to one another and how we have scarred one another. In fact, it took the sacrifice of his son to deal with sin. That is a far cry from pretending it didn't happen.
Regarding the "entrusting" part:
The one time Jesus entrusted himself to abusers was when he was tortured for our sin and shed his blood in place of the blood we would require when others sinned against us. Only Jesus was given that role, not us.
When you hear people quote the scripture "you should forgive because you have been forgiven" with respect to abuse it is likely that they are incorrectly equating forgiveness with reconciliation. It is highly possible that they think you have to put yourself back into a dangerous position to prove you have forgiven someone. That is far from the truth.
God loves justice and he hates the oppressive behavior of those who refuse to be influenced by Him. However, a major way he brings healing and transformation to the world is by calling each of us (when we are emotionally able) to go to our abusers or write to them (with gentleness and truth) and let the other person know whatever it is you want to share. He wants us to do this with a mindset that desires their greater "spiritual" good - i.e. desires that they will turn to God and stop abusing others. This is called "giving them an opportunity to REPENT (or come out of the darkness and open up about how they hurt you and how they hurt God (by hurting what God loves).
Jesus gave EVERYONE this opportunity when he was on the cross. He OFFERED Forgiveness by showing us the pain of our sins. He did this because he desired what was best for us: Reconciliation with God. No one comes to God without acknowledging that they see at least some sin in their lives and that they "need" a savior. God also never tells us that forgiveness is the same as "entrusting ourselves to an abuser again". Jesus even said not to throw "our pearls (what is valuable) to pigs (people who will trample on them".) Our hearts are precious to God. He is a protector. And, he has called us to stay away from people who show patterns of sin that they will not repent of (i.e. anger). Because abuse is a "pattern embodying actions that seek to control or have power over another person" it has to be looked at carefully.
In Summary: Forgiveness is the desire for that person's best (spiritually). It is a mindset that says, "God, this person abused me. You (Lord) experienced this abuse with me. You did not abandon meI was not alone. I am able to empathize with others similarly abused. Yet, I am scarred and need you to heal me. I will not take revenge on this person by killing them or destroying what they love. I entrust them to your discipline and training so that they will not mar your image to others anymore, like they have marred your image to me.