mom says fiance unacceptable

My mom has made it very clear that she does not approve of my fiancé. She has said that she finds his behaviour and attitude to be unacceptable, and that she does not think he is good enough for me. She believes that he does not have the qualities needed for a successful relationship, and she worries about the kind of example he is setting for me. She has said that I should find someone else, someone who is more compatible and who can provide me with the support and respect that she believes I deserve.