I'm not writing dialogue for the ancestors, but I'm writing from my own personal viewpoint. I have a great grandmother, Nellie, who according to the records I've found online, had a baby, my grandfather actually, and gave the baby her maiden name. They appear in the 1900 census living with her mother, a widow, and her four sisters. Then I find a marriage record for her and my great grandfather in 1902, when the baby is two. On the marriage license, it reports that the groom already had a prior marriage and was divorced.
Well now, I can assume that Nellie had an affair with a married man, who was the father of my grandfather.
Then, after they get married, they have another child, Etta. Etta ends up in an institution for the "feeble minded." Nellie had a handicapped little girl and she had to be institutionalized.
I can easily assume and write how hard life must have been for Nellie. She died of congestive heart failure in her forties, after a rough life. I can't actually write dialogue, it just isn't that kind of a book. However, I can tell how I feel about what happened to Nellie, and how I might have felt back in those days having an illegitimate child, living with my family, and having to put my little girl in an institution.
Hope this might help someone.