I have been the break uppee and the break upper.
I usually like to fill out how the other or others think things are going. I was going out with a person and asked how they feel about how our relationship was doing the person was grateful since I opened the topic and found that both of us felt more friendship than romance and decided to just be friends. We are still friends too. I been in a relationship where they felt it was going no where and decide they did not want to continue and broke up with me by text. I was more upset with the way they did it. If they were honest and said in a conversation and I am not feeling it I would be more receptive than out the blue.
I go with the saying treat others the way you wish to be treated. How would you respect a certain way of being broken up with it works for all relationships.