I agree. Not that there isn't any place for lust and libido in a good marriage or that there is anything wrong with either of those, but what are you left with after the passion fades if that's all you had to begin with? If all you had was lust to begin with, the marriage won't last long after that lust wanes because then you will have to deal with the real person underneath it all and you may not find that as attractive as their body once you get past the lust and start relating to the person underneath.