I doubt it.
Perhaps He understands we struggle with it because He knows we're human and sinful but I doubt He thinks its OK.
Jesus told us that if a man looks on a woman lustfully, he has already committed adultery with her in his heart. And I"m sure that applies to women as well.
Sin is born in the heart long before it is manifested in the actions. It's simply a matter of the level of self-control of the individual whether or not they act on their sinful desires.
The problem with fantasy is that it is never as good as the real thing. No matter how hard a person tries to make it good.