Mate to my sister's Ex boyfriend

Taylor and Brittney are what would probably be the closest sisters on the planet. They know everything about each other. Secrets do not exist. What happens when these two sisters' personalities collide as Taylor's ex boyfriend comes back for her, to find that he is Brittney's mate? Even when he doesn't want her, but still Taylor? And what if Brittney's new crush is Taylor's mate? Will these two sisters be able to overcome the ups and downs of their lives and become one again?