Yes, you are absolutely right. It is the readers who are the boss. Like you said, writers need to understand the minds of readers and write accordingly. However, sometimes it should be okay to end a storey with a twist, I believe.

A romance novel can have a sad ending.

A thriller novel can allow a villain to win.

A fiction novel can kill off the most powerful fantasy character whom the audience is rooting for.

I mean, once in a while, a different angle can also help you to explore what your readers were expecting from you.

I understand your case though-you being a romance writer, may piss off some of your ardent reader following.