Not the Man I Thought We Was by Phoebe MacLeod

Madison reckons she’s a pretty good judge of character.
When a disaster at work brings professional photographer Toby into her life, she has him all worked out within minutes. As their work collaboration blossoms into friendship, her preconceptions about him are only strengthened.
The problem is that Madison has got one aspect of Toby completely wrong, and it tears their friendship apart when she finds out. How will she make sense of his revelation and, more importantly, how on earth will she get him to talk to her again?