Disrespect is rude or abusive behaviour that communicates contempt not only for you but perhaps for women in general. Confront a disrespectful man immediately and do not give him the benefit of the doubt. Let the man know that type of behaviour will not be tolerated.
Confront disrespectful behaviour immediately. You do not have to be shrill, demanding or abusive -- just point out that the behaviour is unacceptable to you. If someone you are dating is looking at other women, for example, say in a quiet, calm voice: "It is impolite to look at other women when you are out on a date with me. Please do not do it anymore." It is important in the beginning of a relationship to set the ground rules as to what behaviours are unacceptable, because the longer the behaviour persists, the harder it will be to change.
Do not let the man argue or negotiate with you. Your feelings are valid and you should never have to tolerate behaviour that is disrespectful, even if the man claims not to share your viewpoint. Keep repeating like a broken record, "I understand you have different feelings about this, however your behaviour is disrespectful to me and I need you to stop."
Practice assertive body language. Sometimes men are disrespectful to women because they feel threatened or inferior. The disrespect is designed to put you in your place by intimidation. Allowing a man to overpower you in this way is not healthy for the self esteem of the man or yourself. Show him you are not scared. Face him directly, look him in the eyes and remain calm. These nonverbal gestures send a strong message.
Realise that confrontation alone will not change a man's behaviour toward you if he does not view a woman as his equal. This is not your problem; it is his issue that will hinder all his future close relationships as well. If your relationship with him is casual, it's best to end the relationship and find a more respectful partner. If you are married or committed to him, ask that he seek counselling to work through his issues. If he refuses, give serious thought to ending the relationship.
Seek counselling if you are unclear what constitutes disrespectful behaviour, or you feel you in any way deserve this kind of treatment. Sometimes past relationships can leave emotional scars that need to be worked out in therapy.