Shimon, it wasn’t a hagaah, it was the fact that the rambam in the next few words says what oheva kegufo means by example of how he uses his money. He qualifies his statement by example; if he had just said oheva by itself, or given the example of other chavivus, compliments, etc…then you’d be right.
As to a woman naturally loving her husband more… I’d say that’s a much bigger hanacha and a much bigger chidush; where did you get that from? We know elsewhere that love means giving; that’s not my chidush, it’s all over seforim…ahava comes from “hav”. My only chidush is that that’s the rambam’s kavanah. Your pshat on the other hand, ignores the rambam’s qualification and invents an entirely new idea that women love their husbands more…
I’d say if anything that in my experience that it’s the opposite; men have to win over women more.