The problem comes when "gentlemanly" behavior becomes the dominant trait in a man. The result is, to put it bluntly, a less-than-masculine male. So there is no wonder why women would find a less-than-masculine male unappealing.
For me, and it took quite a while, it became clear that gentlemanly traits are both proper and appealing to women, so long that it does not completely define the man. Creating a balance where one is gentlemanly when appropriate, more dominant and assured when appropriate, and more colloquially "macho" when appropriate, is a great formula for being appealing to women. It also assures that a smart man will not be taken advantage of (for example. being a mover, bank, personal chauffer, etc.).
As the lovely "older woman" in my life taught me years ago (ah, I'm getting misty eyed here!), a woman wants a gentleman to hold the door for her, and a gentleman to pour the wine for her, but when she grants the 'green light,' she doesn't want a gentleman to make witty conversation, twiddling his thumbs, or lacking the confidence to romance her in, lets say, her desired and more base ways.
This is her avice, not mine!!! But I endorse it!
So be a gentleman, I think. But don't be a doormat. And when the lady wants you to cross homeplate, don't be a 'gentleman' standing before her and keep on insisting 'please, after you....."
Just cross home plate, Einstein. You will both be glad you did.
Again, as a disclaimer, be sure she want's you to cross home plate. Leave no room for misunderstanding. Always respect a woman's decisions.