[Fugo shrugs. What can you do, Feferi. Marriage is dumb. Social constructs are foolish. People who are shitty to each other and to children are the fucking worst.]

Yes, that's right. Divorce didn't happen at all in that time period, especially among the working class. Honestly, even if she she was a proper widow, it would probably have been frowned upon for her to remarry at all.

Think of it this way-- Fantine's relationship with Tholomyès is forbidden, because they weren't married. Cosette is physical proof of their relationship. Even though he's the one at fault for leading her on and discarding her, Fantine is the one who has to bear all the responsibility for it.