After days of rumours about the Welshman's future, Quakers chairman Raj Singh released a statement yesterday to announce Davey had quit for personal reasons.
The 39-year-old, who took over at The Northern Echo Arena on April 1, has been elusive since claims that he wanted to resign emerged on Monday.
Neither Singh nor managing director Graham Fordy, had been able to reach Davey, who has been in the US, coaching at the Paul Scholes Academy, in Orlando, Florida.
Yesterday, confirmation arrived via email of Davey's intention to exploit a clause in his one-year contract, allowing him to work a short notice period before turning his back on the club.
It could not have arrived at a worse time for many of the club's supporters, who had renewed their season tickets ahead of Monday's deadline.
Darlington fan Wayne Harrison, 27, said last night: What a kick in the teeth it is, two months before the season starts, especially to those who have just bought their season tickets.
Season ticket holder David Robinson added: I suppose there's two sides to every story but yet again, it's the fans who end up suffering.
Davey was in the process of transforming a squad capable of bouncing back to the Football League after relegation to the Blue Square Bet Premier.
He has moved on 15 of the players he inherited, signed six as replacements, with three more new faces lined up to follow.
Tony Taylor, chairman of Darlington Supporters Trust, said: The manner of the way it has happened is immaterial.
What is important is what is behind it and what has motivated it. If it is personal, then fine, and it is better for the football club. If there's something else behind it, it's better for the fans that we know now.
Andy Smith, of Darlington Supporters' Club, said: The initial news has come as a massive shock. We have been looking forward to the new season and, hopefully, doing well in the Blue Square Bet Premier.
Davey, heavily linked with the vacant managerial job at League Two club Hereford United, has also angered Singh the man who appointed him as Steve Staunton's successor.
But the Darlington chief is determined to contain the damage on the club's longterm aspirations. I can confirm we've had no contact whatsoever from Hereford United, or any other club, regarding his contractual situation here, said Mr Singh.
It's very disappointing.
We gave Simon everything he'd asked for, as we did with the previous two managers, and the rumour we cut his budget is simply not true.
Unfortunately, we've now had official confirmation from him in writing that he wishes to leave. The reason for the delay in making a statement about this was because we wanted to speak to Simon to try to resolve the situation, but he's made it clear he's made his decision.
Davey could not be contacted for comment last night.