Because he loveth all women.
Because he hath not met the right woman.
Because he hath met the right woman and been “disappointed”.
Because he hath many illusions concerning women.
Because he hath no illusions concerning them.
Because no woman is good enough.
Because he is not “good enough” for any woman.
Because he is not ready to settle down.
Because he is already settled down, and is content.
Because he is weak and fearful.