The Stories of Ys Series by Amy Rae Durreson

Life is easy for young artist Heilyn, as he travels between the floating islands of Ys with nothing more urgent to worry about than what to paint next. Then he meets sad, serious Emyr and forms a new ambition. Before he leaves for the next island, Heilyn's going to make Emyr smile. But will a smile be enough? If he wants more, Heilyn will have to choose between his wandering ways and the man he's coming to love.