From today ( 11th January 2018) partners who hope to settle in the UK must be careful not to spend too many days out of the country in the years prior to their application. Absences of over 180 days in a year will mean that they are no longer eligible to settle. It is wise to start keeping a good record of all absences from now on and to keep in mind this new requirement! It is also worth noting the long-standing law that those hoping to apply to become British should generally not have been out of the UK for more than 90 days in any of the 5 years before they apply.
For further clarification on any of the points above please do not hesitate to contact me on firstname.lastname@example.org.