The man suffered serious stab wounds to his leg and arm and remains in hospital receiving treatment. His partner was not injured but was left very shocked following the attack.
The incident occurred at a large detached property on Lands Lane, Knaresborough, at around 10pm on Thursday 14 May 2015.
Jewellery worth a substantial value was stolen during the burglary and detectives are still compiling a list of what was taken.
It is believed that two of the suspects were black. The third suspect, a white man, was much shorter in height – around 5ft 5in tall.
One lead detectives are following up is a white small BMW coupe-type vehicle that was seen speeding through Knaresborough High Street shortly after the incident.
CCTV footage is being reviewed and a number of pedestrians appear to have turned to see the vehicle as it was driven at high speed through the High Street before it turned right at approximately 10.10pm down Gracious Street.
Detective Inspector Nichola Holden, of North Yorkshire Police, said: From the information that has been provided so far, it would suggest that the suspects were quite specific in terms of the items they were looking to steal and the motive is still being investigated.
It may be that the suspects were in the area before the incident and I would ask if the public saw anyone fitting the description of the suspects to call us as soon as possible.
If the white BMW is not involved then I would ask that the driver of that vehicle to come forward immediately so they can be eliminated, as it remains one of our main leads at the moment.
Also the knives used in the incident were described as brightly coloured and again I would ask if anyone has any information about them or has found similar looking knives discarded in their gardens or in the local area to get in touch.
Forensic examinations are still being conducted, as are house to house enquiries and searches for the knives and any other possible discarded property connected to the burglary.
I would like to reassure the public that every effort is being made to identify the people responsible for this incident and bring them to justice.
If you prefer not to give your name, Crimestoppers can be contacted anonymously on 0800 555 111.
Please quote reference number 12150079911 when passing information about this incident.