If the world started with Adam and Eve where did Seth's wife come from?

I was just looking over some genealogy in the bible from Adam and Eve all the way to when Noah was born then the world was washed away except for Noah's family anyway. I was thinking if the world started with two people Adam and Eve then that had Cain, Abel and then Seth. Cain was banished for killing Abel. So that leaves Seth who was born and had many children and so on and so forth.So where did his wife come from the one that bear all of his sons and daughters? All I can think of is that maybe God took from Seth a rib as he did fro Adam and created him a wife? Or is there another explanation because it would just be wrong if he had children with the only supposed woman on earth which would be his mother which would mean we are all inbred or something idk I have always wondered about this.