why girls try to kill their natural feeling of love ?

I hear tips like : do you really think he loves you ? he will he keep loving you if you gained 300 pounds??

these tips are obviously trying to harden their heart until it become like a stone... if the 300 pounds issue is really a matter to you then the answer: if we grow together then I guess I will keep love her. but if I see her for the first time with 300 more pounds then I may like her less, cause after all the love means to love our "other half" so she should have some feature to make her our "other half" which are: to be as similar to be "our" -not a beast like- and as feminine as to be the "other half" , if we are looking only for a body then we would marry to a "female body form" ! ! why then we feel sad when she feel angry and feel happy if we make her smile ? and if she think her body do not represent her then why she get happy if someone tell her you are beautiful ?? and if the body change then also the soul someday die ... it is life ! we are given what we apparently have, this should turn into religion & how we are created or something ....

my idea : instead of killing love inside her she can just secure this love from break up by linking it with commitment (like marriage)

if women are irrational then men should fix things up since men supposed to be the wise side ....