Young adult book about two woman who are friends

Okay so I read this book in middle school so around the years 2010-2012. It revolves around two young women, one lives with her stepmother who always tries to bring her down by talking about her appearance because she is jealous of her and the biggest thing I remember is that she had this red coat that she loves to wear despite her step mother saying she should wear a different color. Then the other woman is in love with her boyfriend/fiancé and she finds out while they are making love one day that he cheated on her with someone he met while working a case, (I think he is a lawyer, all I remember is that they both love each other and that he couldn’t tell her about his cheating sooner because he didn’t want to ruin the case because the woman he slept with was on the other side of the case.) and he tries to win her back and tells her how sorry he is and she ends up forgiving him. That’s mostly everything I remember is there anything you guys can do to help me find this book, please if you have any questions or clarification, I will give it to you if I can if it means finding this book thank you!

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