Before you declare the man about the complete and irrevocable breakup, you should make sure that it's not your momentary whim, but a sensible, informed decisions. And if your relationship has outlived its usefulness, they need to stop. Until you are sure that you want to throw a man, better not to start a conversation. In addition, it would be nice to formulate the reasons for the gap and for myself, and for the later, the question "but why?" wrinkle-free, and clearly and explicitly the points to outline what exactly you do not like.
After the decision to part with the man made, try for several days not to communicate with him at all or bring your communication to the minimum necessary. Not to take the initiative in communication, don't send him a gentle sms. Try rather to realise that your relationship is essentially already completed, then in conversation you will be able to be calm and resolute. Well, man appeared in these days a chill in relations will help to put a little distance from you.
It is not necessary to inform the man that you decided to end the relationship, a letter or message in a social network. First, it can be regarded as disrespectful, and secondly, chances are your partner still wants to meet with you and find out the causes of the incident. So no stretch is fun and immediately get ready to have a serious conversation in person.
Quietly let me know that you need to leave and let it be known that further relationship is impossible under any circumstances. Be ready for questions, grievances, complaints, or insults from him. But try to keep a low profile. Your care is in itself a blow to a man's feelings and ego, so no need to aggravate the situation a splash of negative emotions.
Don't place hopes on the resumption of relations and do not attempt right now to "stay just friends". For the first time after a breakup any communication will be painful. So better to just stop any contact and to stop attempts of men to meet with you or strike up a conversation. Most men in this situation fairly quickly understand what your novel is really finished. And it allows you to end the relationship quickly and irrevocably.