Hi Jack,
At some point, I think we gain a little wisdom, and begin to realise that there is more to life than just desire and passion. When that happens, our choices change, and we choose a partner for their beautiful soul, rather than a beautiful/sexy body.
The world teaches us that there is nothing higher than desire and passion - even calling it love.
After a while, we gain a glimpse of true love, and the appeal of passion is questioned. That's not to say we don't still like to get carried into the heights of passion. It's just that connecting in Love, becomes more satisfying.
Sometimes, it takes a while for this to make sense in our heads, and we create a pretty mess with our partners, trying to sort out what we are feeling, and then find the words to properly describe it.
Entering this process is opening a door to a deeper level of relating, provided both parties are prepared to enter it together.
It is such a shame that most men don't even realise that they are trying to tell their partners, "I love you for more than just your body, and I would like to indulge in Loving with you".
Instead of valuing what was gained, their intellect gets caught up on what appears to have been lost, and they end up saying things like "I don't find you as sexy as some other women ...". While I think this is very much a "Man" thing, Psychologists have shown that the intellect pays more attention to Loss and loss prevention, than to gain.
My wife tells me that she finds Errol Flynn ultra sexy, and I don't mind, because I believe we are together for far deeper reasons.. and when I point out an attactive actress, she tells me why I'm wrong.
In order to fully connect with a partner, Tantrically or just as a natural human, you find yourself progressing through stages - First Sex, then Love, and then Devotion. This is the way to Divine union.
Namaste