It's true. Many times. This crazy little thing called love is powerful, heck the one you love holds so much power. No matter what they do, when you truly love or loved……your first inclination is to protect.
Maybe sometimes we want to protect ourselves too, I mean you chose to love this person….you couldn't have been that bad a judge of character. So by standing up for them/standing by them, in a way, you stand up for yourself. Even though you may feel hurt or betrayal in the process. You know them better than did many people….you understand them just a little bit better, so thus you hold that right to protect. It's your first inclination.