Frisha only has 1 point and she's already said she doesn't expect monogamy. Plus Emily is currently under the assumption that by doing this she's protecting her daughters, even though she has caught me kissing Mira. She knows full well what she's doing, and she was having sex with Marcus outside of marriage so she clearly doesn't hold the same values and doesn't seem too insistent on forcing them on her daughters.
Plot reasons aside, are you saying Emily requires corruption to progress her story? That seems like an odd thing for the walkthrough to leave out given it's been optional so far. Are there other girls where some degree of corruption is mandatory? I've noticed Penny seems stalled as well, though I haven't invested as much time into her as others.