He didn't actually kill himself. He was stressed out from his 老友记 not giving him any 建议 to help his pregnant gf get an abortion. He had no choice but to marry her and he didn't really want to and his 老友记 didn't really treat him well they would use him to take them places also Tony (John) was supossed to call him and that never happened so that's when he goofs off the bridge and he acidently slips off the bridge and gets killed.