A person can only be in `one` household at the date of application. Where a person spends time equally with more than 1 partner, they may choose which household this should be. The rate of tax credit should then be decided on the circumstances of the family in that household only.
Example
Two women in different households have a husband and wife relationship with the same man who spends time in each household. Both women have children and can therefore apply for WFTC, but only one could be treated as including the man in her household. In practice, this would be the household of the woman whose application was determined first by the decision maker.