Not so step son

Ok so this is kind of a confusing issue... my husband let's his ex girlfriends child come over every Saturday and spend the night. He is now six and my husband has been in his life since he was about one... the problem is this child is a complete jerk to me and never listens... he either just ignores me all together or rolls his eyes at me... and for the past three years all my husband says is "he's a child,we will work on it".. lately he also been a huge jerk to our 2 year old daughter... this is our home and I don't think and ex girlfriends kid should b able to come around here and treat us like that! Any advice on how to handle this??