She thought she'd finally had it all. Her name was known throughout the globe. She had the fans. And she had the man of her dreams. At least Misa thought she did. Yes, Light had played the role of the perfect boyfriend to a tee but goddamn it - it's been six years already. It'd been more than enough time for Light to learn how to love her and marry her. But his love was cold and there was nothing she could do to warm him up.
In public, she could see him mentally checking off boxes on how to act, but the second they were alone, he refused to even acknowledge her presence - never mind touch her. If he did sleep with her, it was to shut her up and the whole experience was unsatisfying at best and a bit traumatic at worst since Light didn't care if she were in pain after a romp, leaving her alone as he went off to judge criminals or he did something worse:
Doting on his prized little servant, you.
What was so special about you? Misa mused as she eyed you making her dinner, halfway done with her second glass of wine. Her personal assistant was ill, so Light had begrudingly lent you to her to get Misa off his ass. She didn't understand, you'd even gotten Ryuk to tolerate you. What made you be the one to do what she couldn't - win Light?
Her questions were quickly answered when you started doting on her, stroking her ego in all the right places. You filled the void Light left, making her feel whole again. Soon she found herself bugging Light to let her borrow you after that day. You were gentle, sweet and attentive - everything she'd hoped Light would be. She wasn't surprised when she fell for you. And boy did she fall.