I wrote things too - it gets something across, without it getting clouded in argument; nobody can talk over something that's written down.
I also asked my husband to write to me - I wanted to know (as dispassionately and matter of factly as poss) what he 'got' from the other relationship, in his own words e.g. he said attention, sex, being listened to, feeling desired, being made to feel clever etc etc.
I also wanted another letter which detailed what attracted him to me at the beginning, what good points did I have now and what our relationship would be like in fantasy land (with none of life's distractions).
I told him via letter how I felt (lonely, sidelined, tired, ignored, unattractive, uninteresting etc), what I had first loved about him, and what I still loved/found attractive.
I also made a point of keeping the children separate to the relationship in all discussions - we both love them, they are both of our priority and love/affection etc for them is a given - it was our relationship with each other that was broken.
It's a very, very hard and emotionally draining experience, and I often wondered what the point was and felt thoroughly defeated, angry, sad, pragmatic, drained, hopeful and a whole other range of emotions.