She writes about why someone will be attracted to someone who is attached in a marriage or committed relationship. If the one that person is attracted to was not in a committed relationship then they would probably be less attractive.

Pardon me for saying it, but that is a bunch of hooey. At least from my perspective. Sometimes you just didn't get there first relationship-wise, or weren't quite the right one, but you don't just turn off love, you learn to live with a hole in your heart and try to let it heal over time. Being attracted to someone who happens to be already in a committed relationship happens. And if you can't get over it, you must often absent yourself from that party in order to get on with your life and away from the distraction.

The absolute worst thing in the world is to offer sympathy if you know someone feels that way about you--as if they have an illness (they don't) or don't have free-will to be emotionally autonomous around you (they do). Or to delude yourself into thinking that a tiny little affair won't hurt them, might even help. It will only wound them deeply. Maintaining a respectful relationship is essential, speaking about it is okay if you both acknowledge it, because as you get older you have the perspective to realize that we need to cherish all of our good friends.

Don't gloat if you find yourself in that situation, don't feel flattered. Understand that there, but for the grace of your god, go you. Those are shoes you don't want to walk a mile in. Trust me on this.

SRS