it sounds as though there is an intamcy lack in your relationship and it sound as though by saying she thinks infedelityis forgiviable is a setup for the future.you need to seriously sit down and talk to her.You need to let her in on what you are thinking and feeling.The number one cause of infedelity is a lack of communication,be honest and ask her to do the same see a councelor if need be.Dont put a brand on her because of her mother---my mother is a cheater on my father and they have been married 24years and i myself love my husband and would never.I donot believe it is in her genes to cheat.just find out what she needs and wants and her thoughts on your marriage,