In the ancient and medieval world, soldiers often spent months to years away from their loved ones.
It doesn't help that we don't know when the Warden disappears.
Are you trying to convince me or convince yourself? Because it won't work for me. I'm not about to get in your way though. 
I just think it resonates all the better if she's not romanced. Even her little cameo in DA2, for what little it matters, just works for me better that way. Un-Romanced she says something like "Ah, you've heard of my time with the Hero of Ferelden. I haven't thought about those years for some time". And her present actions reflect these words to me. She both talks and behaves like someone who has moved on. Romanced, she doesn't talk like she's moved on, but still behaves as if she has.
Anyways. It's just about what flows better for me, personally.