Case of polygamy / divorce in 1800s?

[crisane]

In your first post you say

Again in 1861, there are lots of grandchildren living with Edward, who is now listed as widowed. What's weird though is that Mary appears to still be alive and living on Foregate Street (just down the road) with their daughter Margaret.

Margaret is actually living with her father Edward and the grandchildren in 1861
RG9 Piece 2628 Folio 163 Page 41
75 Ch..tt.t..? Rd Gt Boughton
Edward Hughes   60 Gardens labourer
Margaret Hughes 33 daughter  Gardens labourer
Richard Hughes   7 grandson
Emma Hughes   2 granddaughter
Edith H Hughes   12 granddaughter
William Hughes   26 son single jobbing? labourer

This may be William in the 1871 census
RG10 piece 3728 folio 74 page 10
Cheshire County Lunatic Asylum
Upton near Chester Cheshire
William Hughes Age 36 Labourer, Patient/Lunatic, born Great Boughton Cheshire

[crisane]

Birth registration on the GRO index
Birth Richard Hughes    No mother's maiden name- 
GRO Reference: 1853  Sept 1/4 in Great Boughton Vol 8a  Page 321

Birth registration on the GRO index
Emma Hughes   No mmn   - 
GRO Reference: 1859  March 1/4 in  Great Boughton Vol 8a  Page 334

I can't find a birth registration on the GRO index or FreeBMD for an Edith H Hughes  born c1849 +/- 2 years Great Boughton nor are there any without a first name recorded.
There are two registrations with the same vol, page number and registration district for a
Edith Blanche Hooke Hughes/Edith Blanche Hughes Hughes St Pancras June 1/4 1888 vol 1 page 294. "Your" Edith has the middle initial H on the 1861 census."

The only way to be sure of the mother's for Richard and  Emma is to order the birth certificates.