<human>: Can you give me the gist of the text in a nutshell?

So a bit of background information, I'm 21, and she is 19.  I will be graduating college and moving to work across the country.

Anyway, none of that is really the problem.  I've been in a relationship with this girl for the past year or so, and ever since I've met her, she's been gaining weight.  I was very, very attracted to her for the better part of this year, but lately, I don't know.  I am sexually attracted to her, but at times I find myself just not interested.

The difficult part is, she really is beautiful.  Gorgeous face, personality, etc.  Like I really do love her, and her personality, and she loves me for me.  I really do have feelings for her, but I don't know how to approach this loss of physical attraction.

This scares me because I think the answer is to move on.  Lately I have found my gaze wandering more and more, and myself becoming more and more flirtatious with other girls (and I know this is wrong, and I feel guilty as shit for it).  I just don't know what to to do.  Help me /relationships!!
<bot>: Girlfriend of 1 year, I love her, but have lost significant physical attraction, find my gaze straying, what to do?