<human>: Let me start off by saying I have a girlfriend of nearly two years now, so my question isn't about how to be in one.

My previously mentioned girlfriend is one of the most caring, delightful, and gracious people I've ever met, however, no matter how well we get a long I feel unsatisfied.

We've broken up before about a couple months back, because of that feeling of being unsatisfied. I'll try to explain it as briefly as possible, I always feel like the grass is greener. I'll look at other women, sometimes better looking, sometimes not and think "what if" I don't know if that is normal or not, but it is part of this feeling I am having. 

This isn't a new feeling also. My last girlfriend created that same feeling, it was only when she broke up with me (I'm pretty sure she could feel I was unsatisfied) that I wanted her back and when we did get back together (only for a short period) the same feeling came back.

I don't really know why I have this constant feeling of "I think I could do better" but I would love to find out if I just need to end things and move on, or if I am just perturbed and need to realize how good I have it.

P.S Most of the time I feel a lack of attractiveness towards my girlfriends and boredom almost, if that helps. (I'm not a great looking guy, average I guess)

Provide a brief overview of the text.
<bot>: I feel empty with girlfriends I have mostly because I'm not attracted anymore, only until we are broken up and then I want them back.