I loved the human insights you weave into this story. Especially:“I. Love. You.” Sometimes it’s whispered, sometimes it’s yelled. Sometimes it’s mumbled into a warm body and other times it said to a wall. Every time though it’s said with feeling, and every time Seamus says it back.

It’s not a trump card and it doesn’t excuse their behavior. It’s not a cure-all and it doesn’t make their problems go away. It’s never easy and it’s anything but a guarantee.
This is such a true observation about long term relationships, no matter who you are referring to.  I also like that Seamus has his own bitter memories about the war. Often, the peripherial characters' reactions to the war are ignored in fandom.

Good job