Each to their own I guess, as long as you don't make big tits a singular make-or-break factor in your relationships I don't see the problem.
I'm sure everyone has fantasies they enjoy in private but are perfectly content to never see happen in reality. Be it a philanthropic moody billionaire to whisk you away from your boring life, a pair of Japanese twins who want to do the nasty with you or a woman with a very, very small waist and very, very large breasts.
It's all fine, as long as you don't make it a requirement for your relationships. If you do then I would say you have a problem. Your own problem to deal with though, I'd say you'd be missing out on a lot of very beautiful, awesome and nice women. But hey, not my life.