Jean help

I have more of an apron belly so whenever I buy jeans, they are very loose in the crotch area, but fit on the waist and then after I wear them, they become so baggy and so loose, like even less than an hour into wearing them, my waist and crotch and thigh.One time the sales associate told me the type of jeans that would best fit, and I forget what they were. Does anyone know?