Keep your cool and count to 10 before responding to her demands, recommends Preston Ni, professor of communication studies, in the Psychology Today article “10 Keys to Handling Unreasonable & Difficult People.” Taking a breather allows you time to construct a calm and rational response instead of spouting off harsh words.

Demanding individuals often thrive on those who back down from confrontation. Turn the tables by standing up for your rights, Ni recommends. Directly confront your girlfriend. Phrases such as "We need to engage in activities that we both like," and "I need to have a say in relationship decisions," show that you want your needs met but are willing to compromise. Communicate that you expect her to meet you in the middle.

If the demands are causing you emotional distress, identify your breaking point, Ni suggests. For example, tell your girlfriend how you feel about her demands. Let her know that if she is not willing to work toward a more balanced relationship, you may stop seeing her. In addition to consequences, discuss strategies to meet her demands and your needs.

When relationships are causing turmoil to your emotional or physical health, you may need to seek a professional counselor to work through the issues. Schedule an appointment for you and your girlfriend to discuss your feelings about the relationship, mutual respect and expectations. Counseling can help you both recognize problematic patterns and teach you effective ways to communicate with each other, according to the University of Texas Counseling and Mental Health Center's article "Building a Healthy Relationship from the Start."