My wife was always "open" about her abandonment and some of the abuse.
However, it was all a "partial truth" and to be blunt it was a fabrication. I found out that she had lied to me practically thousands of times, both lies of commission and lies of omission. She was so ashamed of what had happened to her, what had been done to her, what she had done (before she met me) that she fabricated this story of her life before me.
There was a hint to it, she had difficulty explaining timelines for about three years of her life. She couldn't really fill those in as we got to know each other, and history would conflict (I have a terribly great memory and many people would never have noticed the discrepancies). I'd ask her about that period and try to make sense of her life story, and it just didn't match. I'd always laughingly referred to them as the "missing years".
There was a mountain of stuff that she had hidden...once it began to come out, it seemed like it would never end.
My wife's affair occurred the year our oldest child turned the age she was when her family broke up the first time. Since she confessed and started telling the truth about her first 30 years, we have seen patterns all over the place....missing years were years she was so ashamed of that she couldn't even think of them or of a cover story.
I'm willing to bet your wife hasn't told you all there is to tell about those teenage years, and possibly other years before she met you.
As for all of us being bisexual to some extent, I can only tell you that that isn't true. I myself don't find men attractive at all, nor am I homophobic and I've worked with a number of gay and lesbian colleagues. I do find women of broad age range and shapes and sizes very attractive. But, I don't cheat, despite opportunities to have done so a number of times. The cheating is not about sexual orientation, it is about being damaged.
The cheating is a sort of abuse and neglect that is plastered onto your family, and it comes from the abuse and neglect that the person has suffered themselves.