So sorry you're having to deal with this. Marriage can be a bumpy road, as you obviously know! I think we all go through rough patches and it isn't until we come out the other side of it that we realize the hard stuff was worth the effort and stress, whatever the outcome may be. I hope that he can read your letter and see your perspective, or at least take some time to realize that he's upset you.
Hope things are looking better for you today.