There's a formula for searching the GRO marriage Index with the ancestry files, it should work but relies on ancestry having transcribed the GRO index correctly and the GRO index being accurate against the original registrations.
I've looked at all the emmas born in thethersett that were alive in 1871 and traced probably marriage entries for each one and then reentered their marriage references and dates and RD district to identify their spouse in the index and so far noen match with a blythe, the possibility is that emma was married a second time to a blythe.
With Lucy, I checked the IGI for a birth o a lucy baptised in Wymundham in the correct or close year, there are 2, i've looked for a post 1837 marriage to a blyth and none match with either of the lucys.
This is a formula that can work as I say , it takes patience and time to cover all the options in case there was a widow involved, i am tired and so don't rely on me having checked thoroughly, but if you have access to ancestry and understand how to work this out you should eventually stumble across the blyth(e) marrriages.