You can apply for indefinite leave to remain (ILR) as a partner either after completing 5 years of continuous residence in the UK with leave to enter or remain granted under the 5 years route or after completing 10 years of continuous residence in the UK with leave to enter granted under the 10 years route.
Any time you previously spent in the UK under the 5-year route will count towards the qualifying period of 10 years when applying for ILR as a partner under the 10-year route, but not vice versa.