Hate to tell heroine this but straight guys rarely are interested in just being friends unless they consider you to be as appealing as a root canal. Also, friends in general rarely put up with harassment about their finances and work habits. Ergo, the whole bit about him being only a friend is a bit delusional.
So our h, figuring out that the H is going to be at an opening for a resort owned by someone she's hoping to land as a client (and possibly other things as well), convinces him to take her along. Only the suite isn't exactly the sort of suite they thought it was. And now she's gotta try to ignore that her other best friend - the H - is hot, that she accidentally got a peep show some time back when he was showering, etc. Oh yeah, and that she kissed him while plastered a day or two before.
She fails. Of course, he doesn't exactly discourage her, since he's been trying to figure out how to get past her barriers.
Eventually, he tells her he wants more than a fling. She gets upset. Storms off. They spend time thinking about it, and finally decide to negotiate.
It lost half a point for her being obtuse and/or dumb enough to think she could have her cake and eat it too. Even if they hadn't had the weekend of hot sex, sooner or later, he'd have gotten tired of being overlooked based on her hangups and she'd have lost the friendship anyway.