He has become this term of "ex-boyfriend" as he has the unnatural ability to judge and assume and does not allow the innocent party to defend or explain her acts at which Mr. Arrogant is so upset about; to which she does not find the desire within to attempt to eplain anymore as it is clearly
not worth it, and she has bigger and better
prospects in her life now to fulfil and
occupy her.
As stated above, the female party in this subject does not wish to
examplify, and therefore to a degree explain as she would not give the "ex-boyfriend" the satisfaction. She knows she is correct and innocent, he has no idea what
actually happened but rathar is relying upon assumption, therefore
he can go on believing he is righteous and be happy within himself and his decisions.