Are there reasons not to forgive?

I've been thinking a lot about forgiveness lately.  I initially had no strong opinions on the subject; rather, I had a vague sense that while forgiveness is a worthy endeavor, there are certain situations where forgiveness would not necessarily be a suitable goal.  After doing some research on the subject, I've adopted a firmer, more coherent position on when I believe forgiveness is an appropriate goal (and when it isn't).  I've come to the conclusion that forgiveness is only necessary when both the victim and the offender want to reconcile and rebuild their relationship.  If there is no desire or intention to repair a broken relationship, forgiveness is unncessary at best and detrimental at worst. 

The currently prevailing models of forgiveness describe it as a process that begins with acknowledging the pain casued by the betrayal and ends with developing empathy for the offender and acknowledging our own falliability and capacity to offend.  We know we have forgiven someone when our negative feelings about that person and his actions have been replaced with positive emotions.

I think back to my own experiences with betrayal.  I no longer feel any anger towards people who hurt or betrayed me in the past, nor do I feel any pain associated with these incidents.  Still, I cannot honestly say that the anger and hurt I once felt have been replaced with positive emotions.  When I think back to a particular time when someone mistreated me or betrayed my trust I don't feel anger or hatred, but neither do I experience a flood of compassion for the one who offended me. 

Historically, when a person has hurt or betrayed me, I have coped with the situation by  acknowledging and working through the negative emotions associated with these incidents; in most cases, I was eventually able to understand the various factors that contributed to the offenders' actions.  Truthfully, I no longer harbor any resentment or ill will towards anyone who has ever hurt or betrayed me.  The caveat: most of these people are no longer a part of my life. 

I'm not the kind of person who is quick to cut someone out of my life at the slightest offense.  Yet there have been people in my life who proved to be toxic; when, over time, I came to realize this, I chose to protect myself by ceasing to associate with these people.  This was never a decision I made lightly.

The problem with replacing negative feelings about a person and his actions with positive ones is that having positive feelings about a person increases the likelihood that you will allow that person to be a part of your life (in some way or another).  In other words, "true" forgiveness increases the likelihood of reconciliation.  If you reconcile with a toxic person who has not changed and thus remains toxic, you enable that person to continue to affect your life in a way that will most likely be negative. 

This assertion is supported by research.  Studies suggest that forgiveness in toxic relationships facilitates reconciliation, even while the offender continues to engage in toxic behavior.  One study found that victims of domestic violence who reported that they forgave their partners for the abuse were more likely to return to their partner (and thus to the abusive relationship).  A recent study by J. McNulty supported his hypothesis that forgiveness can "increase the likelihood that offenders will offend again by removing unwanted outcomes for those offenders that would otherwise discourage them from reoffending."

In sum, I believe that complete forgiveness is not always adviseable.  However, it is not necessary to forgive in order to let go of anger and hatred and move forward with one's life.