going to Catholic schools that didn't even acknowledge that there was such a thing as gay people. Just sinners.
Both my parents were completely inexperienced when they married. By the time Mom figured out about Dad, they had had several babies together -- and she didn't have a career that would give her the means to be a single mother. So they stuck together while we kids were growing up.
As far as the shame being "so unnecessary." Maybe you've forgotten what it was like during the AIDS crisis. No one knew what was causing the disease, and people with AIDs were treated like lepers. I completely understand why she couldn't let go of the secret for years after the divorce.
But she, unlike my sister, was finally able to make her peace with everything. I remember when marriage equality was being debated, and she asked me what I thought. I told her that if same sex marriage was allowed, then gay men like Dad wouldn't be marrying straight women like her anymore. That was the lightbulb moment. After that she told all her friends that she supported gay marriage -- and for that reason.