He provides a lot of information without support. He provides no evidence of this. I'm sure it is true, but it makes me question where this information came from. Instead of using scientific evidence, he often uses poetry. This may be appealing to the married couples reading this book, but scientists do not find this to be convincing evidence.
Marriage is more inviting than the bringing together of two heaps.
Anger can be described in a better way than this. However, keep in mind that the book was written more for the married-couple audience rather than scientists, so these comparisons are appealing and descriptive for the audience he is addressing. I can see this book as being very useful for the married population looking for some guidance in the area of anger, but I wouldn't recommend it as a scientific reading.