My belly so big looks like i'm pregnant, but i'm not. i am abstinent 4 numerous years now.why does my belly look so big; and i am not pregnant?

Weak wall: The strength of the muscles of your abdominal wall will hold or fail to hold in pressure from your bowels. If the muscles are weak the bowels, filled with air , push against those weak muscles and protrude as if "you were pregnant". You fail to say if you are normal weight or not or if you exercise or a pelvic mass was ruled out. Exercises to strengthen abdominal wall would be helpful