life is short, follow your heart. If not possible,

try to leave personal feelings out of work place. 就事論事。

One more point, always present your positive attitude at work, note it's "present".

For example, if the coworker asks you to help her with her part of work, reply her cc boss: "I'd love to. But I have this ... at hand.

Boss, what's the priority that you recommend?", this pushes the ball back to boss and he'd feel bad about the coworker

who brings up the trouble.

-- My 2 cents.