Examine your own behavior and try to see the situation from your girlfriend's point of view. Perhaps you said or did something to make your current girlfriend jealous. For example, if you still work with an ex, or an ex contacts you often for advice or assistance, this ongoing contact can feel threatening to your current girlfriend.

Don't talk about your ex-girlfriends even if it's in a negative way. If you keep mentioning your ex-girlfriends' names, you're constantly reminding your current girlfriend about their existence.

Put away -- or throw away -- mementos, letters or photographs of all your ex-girlfriends. Once a relationship is over, it's best to put reminders out of sight, especially if your current girlfriend is upset by your past. These items might no longer have any sentimental value for you, but to your current girlfriend they suggest that you still have feelings for your ex.

Determine whether your girlfriend is making comparisons between herself and your ex. If she lacks confidence and fears that she doesn't measure up, she'll need reassurance from you about just how wonderful you believe she is. If she initiates comparisons by asking specific questions, don't allow yourself to get trapped into answering, unless it's to reassure her that you honestly believe she's superior in every way. Build her confidence by giving her lots of sincere compliments.

Try to discover why your girlfriend is jealous. She might just have a jealous nature, or perhaps she was hurt by a cheating boyfriend in a past relationship. Examine your response to her anger. Being supportive and kind rather than defensive and argumentative might lessen her suspicion and anger.

Treat your girlfriend with respect and honesty. Dr. Phil suggests that keeping your girlfriend informed of your whereabouts can help reduce her jealousy.

Keep your sense of humor, but don't give your girlfriend the impression that you aren't taking her concerns seriously. If you can interject some humor into the situation you might lighten the mood. Choose an opportune time when you're not fighting to agree on a silly signal to help diffuse an argument before it gets out of control. On the Oprah.com website, Dr. Martha Beck suggests that couples disengage from repeating the same fights over and over by introducing something novel into the interaction. For example, when your girlfriend accuses you of still caring for an ex, rather than denying the accusation or defending yourself as you usually do, try doing something unusual and unexpected, such as standing on your head.