Guruji, is it okay to see someone's beauty? Is it not lust to look at someone's beauty?
You see beautiful things in the world and every beautiful thing should remind you of the divinity. Then the beauty itself becomes a prayer.
This is what is Soundarya Lahari.
Adi Shankaracharya wrote beautiful shlokas (sanskrit verses) called Soundarya Lahari. In that he says that everything he sees reminds him of the Divine. The waves of beauty, it all reminds him of the Divinity.
If you see some beauty and you want to possess it, then it is lust.