Although you may be tempted to be especially nice to your boyfriend to stay in his good graces (and stop him from running into the arms of his ex-girlfriend), this can make you come across as a doormat, warns marital therapist Andrew G. Marshall in the article "Ask Andrew -- My Boyfriend Still Has Feelings for His Ex" on his website andrewgmarshall.com. This is a time to be assertive and deal with any problems in your relationship head on. Don't let small disagreements fester, advises Marshall, and you will both become better at communicating. This helps to build a solid foundation for your future together.

It's easy to overthink something and blow it out of proportion. Your boyfriend mentions his ex's name, and all of a sudden you have a vision of them running off together into the sunset. Try to keep things in perspective. Remember that their relationship ended, and you are with him now. Whatever he feels for her, you have no reason to doubt that he loves and cares for you. It's a waste of time comparing yourself to his ex-girlfriend. Concentrate on your relationship with your boyfriend and try to put all thoughts of his ex out of your head when you're together. When jealous feelings spiral out of control, they can lead to jealous behaviors, which can lead to the end of a relationship. Jealousy stems from a need for control, says psychologist "Dr. Phil" McGraw in the article "Controlling Jealousy" on his website drphil.com. Challenge jealous thoughts with love and respect for your boyfriend and he will value your relationship.

Your boyfriend's ex-girlfriend is probably the last person you want to talk about, but if his feelings for her show no sign of subsiding, you need to discuss them. Let him know how you feel when he talks about his ex or makes it obvious that he isn't over her. Use statements that begin "I feel" so that he doesn't think you are attacking him. Ask him exactly how he feels about his ex and whether he truly believes he can have a loving, meaningful relationship with you, regardless of those feelings. Honesty, trust and respect are all factors in a healthy relationship. By facing up to the fact that there is a problem and talking about it, you are giving your relationship a better chance of survival.

It's difficult to end a relationship, particularly if you are still in love with your partner. In the end, love is not enough, says psychiatrist Fredric Neuman in the article "Coming to the End of a Relationship -- Over and Over Again" from "Psychology Today." If your boyfriend has strong feelings for another woman, you have to ask yourself whether this relationship makes you feel happy, secure and valued. Leaving your boyfriend opens the door to finding the right man -- one who doesn't have feelings for another woman.