SOLVED. Fantasy: arranged marriage, heroine/bodyguard romance, two alternative realities [s]

[Gypsymphony]

I'm looking for a book I read in Australia in around 2010, probably published a decade or so earlier?

Here's what I remember: it's medieval/magic/fantasy, starts with a female protagonist on some sort of pirate ship, she's a princess or something and she's being married off to some sort of pirate/rogue/thief. She realises he's about to sail off with her and runs away (or her father's guards attack to save her, maybe) and this whole plot ensues where she is royal and miserable, having an affair with her big brooding bodyguard fella who I'm sure is called Dog? (Nope, not the one in Game of Thrones!)

This goes on for a while, but the thing ended with her getting to go back to the start somehow (magic? Can't remember, sorry!) and this time she lets the thief/pirate fella sail off with her, I think, and a whole alternate reality happens where they... are happy enough, I think? Maybe avoiding war/chaos etc.

I hope this rings a bell with someone! I can't remember if it was good exactly but I really wish I could read it again :)

[Gypsymphony]

solved by whatsthatbook on LJ! (I can't seem to move the thread on a phone, sorry)

The book was Sky of Swords, a King's Blades novel by Dave Duncan :)