This letter lets a family member know that he or she hurt your feelings without realizing it.
1234, Main Street
Boston, MA 02123
07 April, 2005
<Recipient Address Goes Here>
I don't know if you're aware that what you did was so unkind, but when you <hurtful behavior>, it really hurt my feelings. I know that sometimes we do things without thinking or don't consider the consequences of our actions, and it's easy to hurt others without even meaning to. Perhaps this was simply the case here.
At any rate, I hope that you'll give me a call or stop by so we can discuss this. It's really been bothering me and I want to talk to you about it before it causes either of us any more pain. It's important to me that we settle this -- not just because we're family, but especially because we're family.
encl: <List of enclosed items goes here>