Annette Creegan, 49, of Mitcham, Surrey, was formally identified by officers yesterday after her body was found in the River Bure on the Norfolk Broads on Sunday.
Detectives believe she was dead before entering the water, probably as the result of strangulation.
Her partner, named locally as John Didier, died as the result of drowning. His death is not thought to be suspicious.
Police launched a search for the bodies after finding a 13-year-old girl alone on a boat after a hire company alerted police that the vessel had not been returned on time.
The formal identification of Mr Didier, an NHS worker with family links to Arkansas in the US, has been complicated by the fact he is not a UK national.
It is thought it may take at least another day to obtain dental and other records from his home country to aid identification.
It is believed he committed suicide and might have also used another method, such as an overdose.
The couple, both from Surrey, had been holidaying on the Norfolk Broads with the woman’s 13-year-old daughter for about a week and are said to have enjoyed meals at local pubs.
Detectives are working to establish how long the girl was alone on a boat before she was found and the bodies recovered.
Detective Superintendent Jes Fry, head of the Norfolk and Suffolk major investigations team, said inquiries were ongoing.
But it is understood that the girl, found alone and unharmed on board the family’s rental boat, was cared for and fed throughout last week.
She is now being looked after by family in Norfolk.
Mr Fry said: “All circumstances point towards this being a domestic incident and we will continue to investigate in order to put a full set of evidence before the coroner.
“The girl has been interviewed by specialist officers. Her welfare is our paramount concern and we will continue to support her and her family.”
Police divers launched a search after officers, alerted by hire company Let Boat, found the woman’s daughter on the boat moored in an isolated inlet between Wroxham Broad and Salhouse Broad.