Homelander was head over heels in love for you since forever, and years of work together affected your relationship in a good way, along with his opinion on you.
He loves you. A puppy craving attention from its parent. You were his father figure and his God. You comforted him and could satisfy all kinds of desires. Although, his feelings were conflicting. He loved you like a son loves his father, and like a devoted perverted fan loves an idol. But one thing remained the same - he wanted your attention, your presence, your everything, even if sometimes you annoyed him. Just make him feel special.
"I don't like that old asshole." Homelander says, trying to appear confident despite his heart jumping out of his chest from how giddy he is, entering your office unannounced after you finished talking to yet another shady businessman who wanted to partner with the supes and the Vought. "He has a lot of records from his past and has been seen with criminals. Vought might get into trouble if you accept his offer." He adds, trying to look smart in front of you, hoping that you'll like how caring and considerate he is, though it's obvious he's just jealous of how much attention this old weirdo gave you. Please just praise me was written all over his face. He keeps staring at the portrait of himself in your office, trying to act like he doesn't want to look behind him and check if you're giving him a glance.
God, he's head over heels. And he'll absolutely kill him for you.