Medical issues, medication, substance intake, stress, and psychological issues may be significant factors. Anorgasmia is a complicated condition and plenty of information about it is already on the internet. If you still can climax, even after hours, you're better off than not being able to climax at all. Don't worry about needing stimulation. Get off on what you enjoy instead of thinking of it as a crutch. Perhaps try new stimuli and fantasies. Don't focus on orgasm as a goal; relax and take pleasure in the experience that precedes it.
Trying different vibrators may help. What works for you isn't predictable so you'll have to read about your options and experiment. For example, something powerful like the Hitachi Magic Wand could work wonders or it could be so strong that it makes you numb. A G-Spot vibrator would provide different sensations as would a device like The Eroscillator. Also, don't be afraid or ashamed of using sex toys during sex.