I don't really consider "window shopping" as "lusting after" members of the desired sex. (For me, the opposite sex). To me, "lusting after" someone would be actively trying to have sex with them, whereas noticing a hot woman is just that; a fleeting moment of sub-sexual appreciation.
Yeah just looking is just looking. Active seeking to cheat is something else. There have been a few women I have found sexually attractive but I would never have sex with a women. I think sometime hormones do a thing.