emafia
There are a world of issues that need to be addressed if she has been a sex abuse victim for such a long time. Issues that have to be dealt with if she is going to be able to make the changes needed to make you and the marriage safe in the future.
Has she had professional help with her abuse?
Read up on some of the problems abuse face later in life when it comes to relationships and other issues:
http://www.ncptsd.org/facts/specific/fs_child_sexual_abuse.htmlThere are numerous posters on this board that are either sex abuse victims/survivors or partners to spouse who has been abused.
http://www.marriagebuilders.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=8;t=018568;p=3As you can see lots of people have been her shoes and it has had a profound impact on their adult life and the relationships with members of the opposite sex.
Her abuse is not an excuse for bad choices she has made but understand that she was more likely to make those bad choices than most and more likely to make those choices in a less selfish way (odd to say an affair can be less selfish but for SA victims that can note can be the case). Acting out later on in adulthood is very common among childhood sex abuse victims and rape victims.
So keep this in mind. Understand like I said its not an excuse but it might help you understand her choices better if you understand how many sex abuse victims like her have acted. Also its important that her abuse issues be addressed much like you would want an alcoholic to address a drinking problem as part of working on building a stronger marriage.