What are the motifs in Line of Fire by W. E. B. Griffin?

Relationships are a recurring idea in the book. Since the main characters are in the military, their relationships are often long distance. The men and their women see each other when they can, like Ken McCoy and Ernie Sage. Ernie wants to marry Ken and have his child, despite what Ken and her parents say. She loves Ken and is afraid that he will be killed on one of his dangerous assignments. She wants his child so she has a piece of him if he is killed. He says he will not marry her until after the war.