I can only be attracted to large breasts - help!

This is not intended to insult or hurt anyone - only serious comments please.

I can only feel sexually attracted to women with naturally large breasts.
While I can befriend small-breasted women, and respect them for who they are as individuals, I cannot develop any sexual attraction or bring myself to have romantic feelings towards them.
So far I have turned down 3 women who wished to engage in a relationship with me, largely due to their lack of breasts. While I feel honoured that these women developed feelings towards me, I feel aweful and cruelly shallow that I turned them down (due to breast size).
But the aweful truth remains; I can only be sexually attracted to women who are naturally busty, and thus cannot go against what seems so deeply innate.

I face a few problems with my "fetish".
First, my sexual preference is seen as fitting the "stereotypical" idealization of women and thus many women find offensive, even when I have no intension to offend. Some people go so far as to instantly categorize me as "shallow" or "unintellilgent".

Second, it limits my romantic life significantly, as the majority of women do not fit my "sexual preference".

IIN?? Do I have a disorder of some sort?

*I have never been sexually abused. My mother breast-fed me until I was one. I do not recall any trauma concerning women or breasts.