You can banish their influence, there are standard procedures in banishing spells you can modify to suit your needs. I'm not going to tell you one because I feel you should understand the symbolism behind what you are doing.
This being said, magic is an aid to mundane actions and simply telling someone how you feel about them, whilst will create short term conflict, will ultimately get things done and create lasting results.
You have to be a master of the self thereafter and ensure that you do not fool yourself into forgiveness go back and get hurt again. Banishing someone is all well and good so long as you are ready to rid your mind of them on a psychological and emotional level.