After this, David greatly errors ...and invites a soldier's wife in with him. But as sins done in secret often reveal themselves, a child is conceived.

David tries to mask the sin, by calling for the soldier back from the war to be with his wife ...but the soldier apparently misses the whole point of war, which is to preserve that which is good, such as the relationships that God has created ...particularly that which is established between husband and wife.  David sees he can't mask the sin, seeing this fanatic dedication to war (while lacking dedication to love) ...the soldier is sent to the front lines.  (I don't know, this is just how I see it.)