A Question For Someone With The Answer

What do you do if you really love someone but they are indifferent back?

I would do anything for my girlfriend. Literally anything she asked and I would do it, or at least try hard. Whenever she texts I drop whatever I'm doing and reply immediately and I strive to change both my personality and physique to suit her idea of a perfect man.

She however is largely indifferent towards me. Whenever I see her with her friends she essentially acts like I'm not there, only talking to me to put me down in front of everyone. She continually talks about how 'hot' other guys are and berates me on everything from my hair colour to my muscle tone. When I see her alone it's much better, but because she is apparently trying to avoid getting bored of me she very rarely agrees to meet up, and most of the time she cancels last minute.

I really care for her and would be heartbroken if it were to end, but my question to you is is it better to be heartbroken than downtrodden? Is this even a relationship at all? I don't know what to think right now.