Mat 5:28 But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart.
Looking..not fantasying, not welcoming it... LOOKING
Sexual temptation is willed every time you LOOK, that your eyes are not diverted, that you dwell even for a second on it .
Sin is conceived in the heart and no one knows the heart except God ...LOOKING..LOOKING
To reiterate: being tempted is not a sin.
Looking, an internal act --- a willed action, "Looking at a woman to lust after her" --- is a sin.
We --- you, myself, and Jesus --- are in agreement on that.