I encourage you to stay together and go to DMU together. You two sound serious and have been living together for one year. Medical school is not easy, you will need support from each other. Living appart will be unnecessarily stressful.
Please ignore the comments about how your significant other may not be as serious in this relationship as you may think. She is just blinded by the pre-med drive to "succeed" and be in "the best medical school because it will give most opportunity".
If both of you are living together and you two see yourself getting married then you got it made; medical school is secondary to everything else. Get through med-school and then couples match.
My wife and I were in a similar situation, and we chose to go to a D.O. school together and it was the best choice I have ever made.