De Boer led Ajax to last season's title after taking over from the sacked Martin Jol in 2010 but his chances of a repeat success were undermined when club legend Johan Cruyff became involved in a bitter and unsettling boardroom dispute.
The side's pre-season targets of a successful title defence and to reach the knockout stages of the Champions League looked doomed to fail when a run of five domestic matches without a victory left them well off the pace in the league standings.
Ajax failed to achieve their Champions League goal and the internal power struggle intensified in February when the other members of the five-man board of commissioners appointed Louis van Gaal as the new club director behind Cruyff's back.
"That was not a pleasant period as the club was divided into two groups and several people acted strangely and were avoiding their rivals," De Boer was quoted as saying in Dutch weekly Voetbal International.
"For me, it felt like I had to choose between a son and a daughter in opting to take the side of either Cruyff or Van Gaal."
"I supported Cruyff publicly as he had asked me to and I also agree with his technical and tactical blueprint for the club," De Boer added.
"I was also disappointed in Louis van Gaal as he had kept Cruyff in the dark when he was appointed."
"At that moment, we were in a very poor phase, we played bad and had several injured players," De Boer recalled.
"I remained positive and told my squad that our goal should be to win the seven matches before we faced PSV and to make that clash our cup final.
"That match [2-0 win] gave me the most satisfaction, the result was good but the way we played was close to perfection. Our positional play was great and we pressurised our opponents as a complete team."
His task will be made that much harder with skipper Jan Vertonghen and right-back Gregory van der Wiel both attracting attention from a number of Europe's bigger leagues with expected bids for their services likely to test their loyalty.
