Sit down and let your girlfriend know that you do not think the fact that she continues to communicate with her ex-boyfriend is appropriate or acceptable in light of the fact that this is someone she was physically intimate with and shared her secrets with. There should be no phone calls, emails, texts or visits with an ex-lover, according to the staff at eHarmony. There was a reason your girlfriend and her lover broke up, and now she is devoted to you. Express your desire for her to affirm her devotion by respecting you and cutting off ties with her ex.

Even though you are threatened by your girlfriend's involvement with her ex, there may be a reason you cannot see that they are continuing to communicate or spend time together. Ask your girlfriend to open up to you and let you know why she feels the need to talk to him still. Perhaps she is hurting for friends and wants more social interaction. By figuring this out, you will be able to help her find a solution to her problem that does not involve her ex-boyfriend.

The two of you must sit down and create a list of acceptable and unacceptable behaviors in your relationship. While it may seem a bit extreme, it will help you get on the same page as your girlfriend while clarifying your needs and desires. You must come to the agreement that spending time with an ex is off-limits. However, perhaps spending time with another member of the opposite sex is acceptable. There must be some freedom in your relationship, because if there is not, it may lead to tension and rebellion, according to Christoph Kreitz in "Boundaries in Marriage."

If your girlfriend continues to disrespect you by spending time with her ex, it may be time to walk away and end the relationship. While she has the freedom to do as she wishes, there is only so much you can put up with as her lover. You become vulnerable when you commit yourself to one person, and being continuously hurt will only lead to bitterness and confusion. Whether she returns to her ex-boyfriend after your relationship is over or stays single, you should not have to beg your significant other to be devoted to you and you alone.