EXOD442 Hashem wants the world to function without any mixing of different species. Similarly, he wants every human being to know the identity of his father. What is more, if one does not know the identity of his father, he cannot be certain that he will avoid violating Torah prohibitions on forbidden relations, for he will not know which individuals are his relatives. He might marry someone who is forbidden to him. In addition, adultery is a type of theft. It also leads to murder--for the wronged husband his liable to kill the other man. These are just a few of the problems there are likely to result from adultery.