Louisa Deitlein appears in the 1871 census living in Bloomsbury, London. She is listed as being a Surgeon’s Housekeeper, she is married and her relationship to the head of the household is wife. Her census entry appears as the first on the page but the proceeding page does not appear to relate to her at all. As her age is given as 40 years old this would put her approximate date of birth at about 1831.
The GRO marriage index has an entry DEC Qtr 1864; St Giles, London; Vol 1b Page 778. This shows that Robert Anton Albert Dietlein married one of three women also listed on the same page, these are: Johanna Donohue, Louisa Wallis or Louisa Woolley. The entry for Louisa Wallis had the district as Clerkenwell while the other two are for St. Giles. The most likely candidate therefore would be Louisa Woolley.
Robert Dietlein is not to be found in previous or future census returns and remains unidentified. Obtaining the certificate of marriage is likely to reveal more.