Fantasy with a good slowburn romance subplot

And I am afraid I'm a sucker for the famous trope of the male protagonist being reserved, possibly aloof, unused to **feelings** but working his way through it.
I'd also prefer the female protagonist not to be the carefree "sunshine" type, rather someone clever, not too loud, reserved maybe.

Ideally there are novels beyond YA/romantasy, I am craving something somewhat more complex...

Any recommendations welcome.