If she means you are small physically as far as your physique then it's merely a comment and she married you for love and not your physical appearance. If she means 'small in your character' this means you could be narrow minded; cheap, etc. If she is mentioning your penis is small then she knew what you looked like before she married you in most probability. Remind her it's not the length that counts or the width, but how you use it and you had no complaints before she said something. If she said this because you were arguing then it would be to your advantage to start communicating with each other on a better basis and ask her why she would say such a cruel thing and it is no different than telling her she has a fat butt; no boobs or is too fat! Don't let her get away with it.
