A fungal infection around the private parts that has lasted for 3 years is likely a chronic or recurrent infection that needs proper medical treatment rather than repeated self-medication. It is important to consult a dermatologist, as you may require a full course of oral antifungal medicines along with appropriate topical creams to completely clear the infection. In the meantime, keep the area clean and dry, wear loose cotton underwear, avoid tight or sweaty clothing, and do not use steroid-containing creams, as they can worsen the condition. Wash and dry clothes and towels separately to prevent spread, and continue treatment for the full duration advised by your doctor to reduce the chance of recurrence.