Not Written in the Stars by Piper Scott

Houston… we have a problem.
Ezra Miller’s life has been turned upside down ever since his best friend hooked up with an alien named Al, and not just because he walked in on them having close encounters of the third kind. In the year since he discovered the truth about extraterrestrial life, Ezra has accidentally become the sole person the Darvrokian race trusts to act as Earth’s intergalactic representative, which is great and all, until he’s assigned a Darvrokian coworker plucked out of his worst nightmares.
Titan Leon is everything Ezra hates in a man. He’s arrogant, presumptuous, and worst of all, hot enough to make Ezra forget why he hates him in the first place.
Hot enough that “absolutely not” turns into “only this one time.”
Hot enough that Ezra can overlook the fact that he’s Al’s most disliked brother.
But one time isn’t enough for Titan, and he won’t take no for an answer.
He’ll do whatever it takes to make Ezra his.
And sure, he’s an asshole… but as much as Ezra hates him, he can’t help but see that there’s something softer about him lurking just beneath the surface. SomethingTitan only lets Ezra see. And whatever that something is, it has its hooks in Ezra so deeply, he can’t help but fall into bed with him over and over again.