There is no name listed so his lover can be whoever you choose, although this was written with Severus in mind.
Harry loved quills. He loved the feathers for tickling. He loved the way ink looked painted on the pale skin of his lover, and the way it smudged when he stroked the trembling flesh beneath him. He loved the way the ink stained, marking his lover under his robes. At times he touched the ink to the man's face and forbade him glamours. To watch his lover's fight to remain stoic brought him such joy. But, most of all, he loved watching his lover's face and hearing his begging moans when he carved his name into his lover's willing flesh.