Research shows that learning to forgive or being a forgiving person helps you feel better physically. The reasons are simple. It is very stressful to be constantly at war with certain parts of your life. Telling yourself again and again that you got a raw deal because your husband does not love you the way you want to be loved is hard on your heart and nervous system. Blaming someone who does not care about you enough for the way your life turned out is incredibly stressful. Dwelling on the ex who didn’t love you and has since moved on puts a strain on your nervous system and does not slow your ex down at all. Finally, it is stressful and ultimately self-defeating to complain about things you can’t change in your spouse. If your wife is messy and has always been messy, constantly expressing your displeasure about it will not do your muscles or arteries any good. Nor will it make you or her feel better or get along any better.
The reality is that resentment and stress can further damage your relationship as well as your nervous system, while forgiveness can reduce the harm caused by these negative feelings. By forgiving, we are able to let go of our resentment and reduce the stress it places on our body.
— Dr. Fred Luskin, Forgive for Good, p. 31-32