As a therapist, I wanted to say, "YES! Yes you are dating the same person over again, and if you dump her, you will find one just like her again! It will take some work, but you can change that. Just come see me for a few sessions, and we'll see how different the next girl you pick up can be."
The sad but comfortable truth of it all is that we as humans tend to play out difficult relationships from our past until we can get them right. Seriously, it's like we haunt ourselves with relationships dynamics from the past until they play out differently, we get sick of it and change it, or until it kills us (literally, this is one of the main reasons that people in abusive relationships continue to go back, or go on into another abusive relationship after leaving one, it's what they are used to and feels normal).
Now I'm gonna say something you likely don't wanna hear, but the truth of it is that often that 1st relationship (the one you play over and over again) wasn't in a choose your partner situation, but instead was a parent or leading adult role during your childhood. Now as an adult you continue to be drawn to people who are like that person (treat you like they treated you), and continue to interact with them hoping to get something that you couldn't from your original adult figure. So, sorry to make you have to think about this, but if you feel like your relationship with your partner is the same as past relationships, consider thinking about how closely that relationship may mirror a relationship you have with one of your parents/caregivers. You may be saying right now, No way, I didn't even know my dad. But wait, is one of the main issues in your current relationship that you feel like your partner is never around? Hum... who is that like? Or you may be saying this person is in no way like my dad,..well what about your mom? Just because you are a female doesn't mean you will carry out a dynamic like the one between you and your father, it could be you and your mom, or you and your grandma.
But here is the good news. You don't have to continue to stay in unsatisfying relationships trying to to get a resolution you could never get with a parent. Instead you can suck it up and acknowledge that there is an issue here, and that you need to do some self work. Then, if you are really brave, go see a therapist. If you're brave but a little scared, talk to some trusted friends and consider a self-help book (but be careful, a lot of those are crap). Most importantly do some self- work. Get in touch with yourself and find out what you are craving from that first relationship, then figure out how to get it from yourself. Ouch, that is hard, but if you do you'll be able to enter into relationships in a whole new way, (or stay in your that completely frees you and your partner from your old crap. Wouldn't that be nice?