To love someone that's with someone else (commited) is not a sin, but to commit yourself to that person that's the sin. You can't just judge a person this or that just because of what you see from the outside. There is always a story behind each action of a person. Being a mistress is something Cardilyn can not be proud of, but being in love with a person who treated and love her beyond expectation. Can you even blame her?