I am not sure what you are speaking about. (and I am unsure I got across what I was speaking about)
There are areas where women are very strong. (like men are strong in picking up and moving things) A families emotional welfare is one place where women are exceptionally strong. So, not at all comparable to fragile.
I speak of fragility, like you would think of a rose. Once opened, it is only with us for a little while, and strong winds or heavy rain will make its life shorter. Very fragile.
A woman's sexuality is very fragile and easy to corrupt. Women are designed to take things in. This includes all the energies of all the men they have slept with. Women with higher men counts are less fertile and much more likely to have sexual organ problems. (and more unlikely to be happy in a marriage)
The other piece, that almost no one talks about, is the society of a husband/wife dynamic.
Without a wife and family, a man will work at about 20%. That's all he needs to in order to survive himself. A man with a wife and family will work much harder, and thus the society benefits from the extra production. But, in exchange, the wife and family need to be his. With each other partner then woman has had, this bond is diminished. 1/2, 1/3, 1/4, 1/5th...
So, our current society asks men to perform at 100%, while getting a wife that is 10% or less.
And, the most important thing is that the man is raising his own children. That bond is extremely important. This is the reason infidelity is so bad for society. Currently, according to a technician who does blood samples at a hospital. 1/4 of children are not the father's. Just based on blood types.