Speaking after the hearing at Eastbourne Coroner's Court, Magdalena Apperley said: "We didn't get closure.
We will probably never know what happened to Andrew.
Blackfriars Bridge Opened in 1869 by Queen Victoria.
Relatives of Andrew Apperley, 38, initially feared he had been murdered when he went missing after the notorious gathering on the island of Ko Pha Ngan on 12 February, after sending them a host of cryptic Whats App messages.
Shortly before the father-of-one died, he sent messages which said: "OMG had a mad night, all the guys wanting [to] kill me," followed by another which spoke about a "scary guy with the face mask", an inquest heard on Thursday.
"But in terms of my job as a coroner it's hit and miss as to whether I will get useful information or not.
"I'm not getting sufficient or sufficiently reliable information.
Mr Apperley's wife Magdalena said she felt she would never know what truly happened after a coroner recorded an open verdict at the inquest into his death.
She and his mother Linda criticised Thai authorities for the lack of information provided in the investigation after he was believed to have drowned.
I think it's down to resources." Mr Apperley had a history of drug taking, liked to party and regularly visited Thailand, the inquest heard.
Mr Craze said the post-mortem found no signs of a struggle, bruising or trauma, adding: "He led a bohemian lifestyle, he took drugs.
It was presented to the British people in 1819 in recognition of Nelsons victory over the French fleet at the Battle of the Nile in 1798.
This Palladian building was erected in 1786 when the river still reached its walls.
It takes its name from the Duke of Somerset who started a palace on this site in 1547. This includes two of the four Inns of Court - the Middle Temple (in whose Elizabethan Hall Shakespeares Twelfth Night was performed in 1601) and the Inner Temple.