The Love Hypothesis by Ali Hazelwood

Third-year doctoral student Olive Smith doesn't believe in long-lasting romantic relationships, but her best friend does. It took more than a sleight-of-hand Jedi trick to convince Ann that Olive is in a relationship and living happily ever after: scientists need evidence. Scientists need evidence. So, like any self-respecting biologist, Olive panics and kisses the first man she sees.

That man is none other than Adam Carlsen. That is why Olive is truly surprised when the reigning tyrant of the Stanford lab agrees to keep her pretend secret and be her fake boyfriend. But when a big scientific conference goes awry and Olive's career is put on the Bunsen burner, Adam is unyielding in his support and even more unyielding . . six-pack abs, he surprises her again.

Suddenly, their little experiment is in danger of combustion. And Olive learns that the only thing more complicated than a hypothesis about love is putting her own mind under the microscope.