the brother...webmaster is 100% correct.
He that looks upon a woman to lust after her hath committed adultery with her already in their heart.
this is in islam too. even though u didnt physically commit adultery as soon as some thought runs through ur mind about a woman being engaged in any physical act with u...or the woman alone is thought of naked or whatever...stuff like that..u've already committed the sin of adultery.
May Allah give us the hidiat(guidance) to stay on the right path and save us from sin.