This may be your personal preference, and I don't want to knock it, but I do fear that this is really a game of semantics. When a man calls a woman whom he fancies or is presently courting etc. 'beautiful', while it's possible he may mean it in the strictest sense of the word, more often than not I'd bet that he is using the word at least partly as a synomym for 'sexy'.
Think of it like this: a man can call the whole of creation beatiful (for it is), yet there is something even more to you that is additional to beauty: you are sexy to him. If he doesn't find you sexy then I'd question whether the relationship would be a fruitful one (and I suspect that you would too). This additional element is why your man will ultimately want to marry you and start a family. It is something unique within the relationship between a man and a woman that is not found in the relationship with the rest of creation. Even though we can still rightly call the trees and the birds beautiful, I don't think you'd want your fella copping off with the nearest sheep.
