Buzz Bissinger owns more than 100 pairs of leather pants and over 200 pairs of leather gloves, having spent more than $600,000 on leather goods in the span of three years. Mr. Bissinger has a spending addiction, but when he published his confessional in GQ magazine he was labeled an “obsessive,” a “fancy man,” and a “shopaholic.” Only when he was admitted into rehab did many people understand that he was struggling with a debilitating behavioral addiction. Mr. Bissinger joins the Sugars to offer guidance to a letter-writer whose therapist and family …