One in five couples admitted to reading a partner's emails or text messages, and 13 percent examined their partner's internet browsing history. More than 2,400 individuals were questioned in the research.
Six per cent of the couples had met online, of which over a third had met at an internet dating site and 19 percent in a chat room.
Online daters choose more diverse partners, according to the research, as 36 percent of the 'online' couples had different levels of education compared with 21 percent of 'offline' couples.
Bill Dutton, director of the Oxford Internet Institute, said: "This study is a dramatic illustration of the potential for the internet to reconfigure social relationships."
The survey also found strong evidence to suggest that couples believe 'online' relationships to be just as important as 'offline' ones.
Around 85 percent of respondents disapproved of a partner 'flirting' online with someone else.
This rises to 89 percent for 'communicating relationship troubles to others', 94 percent for 'having cyber-sex' and 97 percent for 'falling in love', raising interesting questions about the three per cent who are fine with this.
One of the biggest areas of disagreement is on the viewing of pornography online. Some 46 percent of couples disagreed on its acceptability, but men are apparently much more tolerant than women of this activity.
Couples turn to online espionage
By Iain Thomson on Apr 9, 2008 1:04PM