A relationship is a complex dance that occurs between two people. Each phase represents a spoken or unspoken negotiation of boundaries, rules and expectations. Some people prefer to keep things light and casual, while others see dating as the precursor to marriage and kids. There is no right way to have a relationship, but things get complicated when both partners are not on the same page. If your girlfriend thinks you are in different places, she means that you do not view the relationship the same way.

Considering Life Stages

A difference in life stages can have a profound effect on a relationship, says relationship expert Lisa Steadman, as cited in the Fox News magazine article, "5 Pitfalls to Dating Older or Younger." In adults, this usually means an age difference of more than 10 years. In high school and college, however, even a small age difference can have a major effect. For example, if one of you is graduating and moving away, that person might be looking toward a more adult future while the one who stays behind wants to enjoy the rest of her school years. Discuss the effect of upcoming changes in your lives and decide together how to proceed.

Progressing the Relationship

While all relationships are different, they generally progress through a series of phases. PsychCentral.com identifies five relationship stages that couples experience along the path, from infatuation to true love. Some stages are painful, and force couples to confront the fact that real life does not end just because they are in a relationship. People seemingly fall out of love, only to rediscover their passion a few months or years later. When you are both in the same stage, you can work through it together. When you are out of sync, however, it is easy to feel like you are living in different worlds. Have an honest discussion about the way you see each other and view your relationship. Allow the person who wants to progress more slowly to take the lead.

Making Sacrifices

Relationships take a great deal of work to maintain. Over time, healthy relationships are generally balanced, with each partner actively participating in give and take. At any moment, however, one partner might need to give significantly more than the other, notes psychologist Amie M. Gordon, in an article for The Greater Good from the University of California at Berkeley. Your girlfriend might feel that she is sacrificing more than you are, or she might feel unready to make certain sacrifices to maintain the relationship. Work together to consider the sacrifices that each partner makes and negotiate compromises that enable both of you to be comfortable.

Expectations and Obligations

In an article for Psychology Today, Dr. Mark White points out that expectations and obligations are inherent but often damaging in a relationship. He suggests that in a truly harmonious relationship, both partners are free to do whatever they like, but both make the choice to do things that support the relationship. He also admits that this utopia is nearly impossible to achieve. Regardless, people in intense relationships tend to get wrapped up in an ever-longer list of obligations to the relationship. Perhaps your girlfriend feels you are demanding, or she might feel that you are not meeting her expectations. Hash out the topics that are repeated sources of stress or arguments.