One thing I didn't include in my letter and wish I had - ask for forgiveness. It's in another book I'm reading, Desperate Marriages by Gary Chapman. My letter read was full of apologies for my feelings or behavior but I didn't ask for forgiveness and when you extent the invitation to forgive, it gives the receiver a choice to soften their heart to you or not. Very empowering and I wish I'd included a 'hope you'll be able to forgive me at some point'.
