Wanted By the Hitman by Tarin Lex

When your best friend is a contract killer, you get good at keeping secrets. Just don’t fall in love with him. Because it turns out, hitmen can keep secrets too…
He was the quiet, mysterious guy next door. Then one night, four years ago, he became my savior, and I didn’t even know the extent of it then. Now he’s my best friend, my roommate, my protector. I keep his secrets close to the vest. He keeps our physical boundaries in check.
One day. All it takes is one day for secrets to start spilling over, putting us both in danger. He thinks I can’t handle his deepest, darkest secret yet. I think he can’t handle mine. I’m more than his friend and confidante. I’m hungry for him. I’m obsessed.