The relief that he saw wash over Cole's face was a good thing. It helped Castiel feel that he was still capable of good, even though he was sinking further into lies atop of lies. Cole's pain was lessened some and perhaps the knowledge that his lover was safe could assist him in some way. Castiel hoped so. Having never had a mate, he didn't quite comprehend the significance past her being significant.
He shoved his hands into his pockets and stood next to Cole, staring out at the city. It was loud and largely inorganic. During his brief time as a human, he recalled the feeling of claustrophobia and he assumed he would feel that way were he viewing it through human eyes. Humans were curious creatures - they proposed to enjoy the wide open, however many of them lived like this. Castiel didn't seek to understand it.
"You are welcome," he replied softly. "I can see now...why you carry her name on your body."