According to Osho, your arousal on seeing a beautiful woman is a natural animal instinct, intensified by long cultural repression; it’s simply recognizing beauty, not a sin. Don’t feel guilty or repress it—accept it consciously. With awareness and respectful expression (not a pornographic, objectifying gaze), energy becomes refined and can be transcended; only a buddha is beyond such excitement.
Your body reacting to beauty is normal; notice it without shame, be respectful, and with awareness it will naturally loosen its grip.