South Wales Police says "new and significant information came to light" which led to the case against John Clifton Davies to be dropped.
He has criticised the force for holding him for 16 months without bail, before finally speaking to key witnesses.
In 2010, South Wales Police launched an investigation into the death of 39-year-old Colette Davies which occurred in India in 2004.
Following a joint investigation with Himachal Pradesh State Police in Northern India and in consultation with the Crown Prosecution Service, a 50-year-old man was charged with her murder and fraud.
During the investigation which continued following the charge, new and significant information came to light which has been reviewed by the CPS.
As a result of this review it has now been decided that proceedings will be discontinued.
More top news
Extremists are using rural parts of west Wales to train and radicalise people, that's according to an officer from an anti-terrorism unit.
To mark World Autism Awareness Day, Welsh care group Orbis are launching a new campaign to change the way Autism is perceived.
This TV election debate represents the biggest chance that any Plaid Cymru leader has ever had to make a mark on a UK election.