The warning for the deputy prime minister came from a Liberal Democrat voter in a question-and-answer session in Bristol.
Members of the invited 300-strong audience accused Clegg of failing to secure the key Liberal Democrat goal of electoral reform, supporting “brutal” social policies, ignoring tax avoiders and overseeing “dangerous” cuts in the NHS.
One participant, lawyer Shazada Hayat, likened Clegg’s alliance with the prime minister to the celebrity marriage between Cheryl and Ashley Cole, which ended in acrimonious divorce after the footballer’s infidelity.
Hayat told him: “How long is this marriage going to last? Only you know. But what I would like to ask is, is this marriage going to end amicably, or is it going to be like Cheryl Cole, you will be screaming that ‘I’ve been betrayed, betrayed, betrayed’.”
Hayat said many Liberal Democrat voters were dismayed by the coalition government’s cuts, which were adversely affecting students and older people.
“I’d just like to say to you Nick, just like Cheryl Cole was advised – get out while you can, before it is too late,” he added.
Clegg defended the Liberal Democrats’ record in government, claiming the party was pushing for fairer policies, for example, the restoration of the earnings link for state pensions from next April.
“Much as your [question] was elegant and humorous, please do not just glibly pick up whatever a headline says,” he said.
“We have taken decisions already which have sought to make sure that we are doing difficult things as fairly as possible.”
The event is the latest in a series of public meetings which Clegg is holding around Britain.