Yes, what you are reporting is absolutely normal. As you said quite eloquently in your letter: At that time in your life, you were turned on by thinking of any female. It makes sense that you would get aroused by the woman in your life you most loved at the time.
Fortunately, part of growing up is learning impulse control. As you got accustomed to your hormones and learned how to manage your physical feelings, your ability to manage your emotional feelings followed. You’ve now turned your attentions to women who are appropriate and available to you.
Please stop feeling guilty about a normal chapter in your development.
I wish you well.