He reckoned he'd probably be in a retirement home, possibly called Sea View, possibly in Clacton, inhabited by run-down marketing directors from the newspaper sector, including Ellis Watson - the other half of a notorious terrible twins act that Constantine was part of at the time.
One could easily imagine the two of them as mischievous old buggers, secreting bottles of whisky under their travelling rugs.
The mid-90s were heady days, of course, for Watson, the marketing boss of The Sun and the News of the World, and Constantine, his counterpart on the Times titles.
Constantine was Rupert Murdoch's commander on the ground during a price war that saw The Times' circulation surge to a whisker short of 850,000 from a base of around 360,000. The pair could afford to make jokes about mortality back then because they were, by most people's reckoning and not least their own, immortal.
A full decade isn't up, obviously, but we now have a fair idea of how it has panned out for Constantine. He's been once around the block, including a walk on the wild side of the dotcom boom as a would-be digital media entrepreneur and a spell trying to get in on the ground floor of wireless internet; now he's back in the inky fingered world of newspapers.
Last week, he was appointed to the newly created position of the vice-president of global marketing and research at Metro International, the publisher of commuter freesheets in 16 countries around the world.
Constantine's task will be to give that disparate (and with major gaps such as London, somewhat patchy) network a new level of
coherence in marketing terms. In the UK market, Associated Newspapers famously got there first with its own Metro title.
Metro is now to be pitched as "the world's largest global newspaper" and one of the world's most powerful media brands - a multimarket, multinational title which captures a similarly young and affluent demographic across all its 28 editions.
But doesn't it feel a little strange for Constantine to be coming back to the newspaper business? After all, when he left to join the dotcom bubble, hadn't he implied that newspapers were condemned to terminal decline? Well, perhaps, he concedes, but the world looked very different back then. And he absolutely challenges the implication that he's back to square one.
"Yes, we still cut down trees, pulp them and cover them in ink," he states "But Metro is a totally non-traditional newspaper. Its launch back in 1995 was the most revolutionary event in newspaper publishing since I don't know when. Free is the future of news-paper publishing.
Traditional publishers are under-servicing the younger readers so they are leaking them at an unsustainable rate.
"The revolutionary idea with Metro is a commuter title which will tell you everything you need to know about the world in 20 minutes, in a very straight and objective way."
Constantine is markedly mellower than he was in his Wapping days - and those who know him say that's hugely good news. They say that the manic, aggressive (and sometimes juvenile) posturing demanded by News International tended to obscure the more naturally urbane and sophisticated facets of Constantine's character.
And it would be true to say that Constantine's many fans in the business prefer the sophisticated side. He has charisma, considerable charm and is very funny, particularly as a mimic. In the old days, his party piece was to relate the events of major News International meetings, doing all the voices. He was particularly adept at taking off Murdoch.
"Although the News International experience stands him in good stead, this new role bears little comparison with what he did then," Jim Kelly, the chief executive of Rainey Kelly Campbell Roalfe/Y&R, says. "In fact, I don't think he would ever have contemplated returning to a UK-only newspaper job. This is about a global brand and a wholly different challenge. And from Metro's point of view it's a brilliant hiring."
So he's not ready for Clacton quite yet. And actually, Constantine, who says that the international demands of the new job will dovetail with his love of travel, has something more exotic lined up. He's the joint owner of an island off Borneo, complete with a hotel that accommodates 24 and features some of the best scuba diving on the planet. It has an almost legendary status in the diving fraternity because the waters are alive with giant manta rays.
It is, he says, stunningly beautiful: "You can walk round the island in 25 minutes. The turtles come up every night to lay their eggs. It's Robinson Crusoe with diving chucked in. I drift off to sleep every night thinking about it."
The Constantine file
1991-95 Marketing manager, Sun and News of the World
1995-99 Marketing director, The Times and Sunday Times
1999-2001 Business development and content director, Talkcast Corporation
2001-2002 General manager XT Marketing
2003 Vice president of global marketing and research, Metro International
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This article was first published on Campaign