Dumbledore wore the cursed ring primarily due to a moment of weakness and a desperate longing to reunite with his deceased family, particularly his sister Ariana.
He succumbed to the temptation of the Resurrection Stone, which was embedded in the ring, and hoped to see and apologize to his deceased family. This desire clouded his judgment, causing him to momentarily forget the ring's identity as a Horcrux and the potential danger it posed. In his haste, he put the ring on. This action immediately triggered the powerful curse placed upon it by Voldemort as a defense mechanism. The curse quickly began to spread, poisoning Dumbledore through his hand. He did not wear the ring out of malice or ignorance; it was a lapse in judgement brought on by deep personal loss and the temptation of seeing his family again.
