We all know relationships are work. What we don’t often hear is that work is a relationship. And sometimes, the relationship is abusive. Good examples from the @Work Advice inbox:

My boss is a bully who treats me worse than others. I’m beginning to wonder if I’m even good at my job anymore. I cry pretty frequently (not at the office) about the constant criticism and the ridiculous deadlines.

My boss’s expectations are never clear. She gets frustrated when I ask her to clarify. She changed her mind four times in 90 seconds the other day.

I’ve been working with someone who is a toxic garbage nightmare. I’ve been getting more tense and withdrawn.

Karla: It may start out fine: A dream job sweeps you off your feet. It starts to have ups and downs, but you hang in there. Then one day you realize you’ve driven home in tears every night for six months. You’re dealing with management promising your clients the impossible, a clinically sadistic boss, a harassment campaign that no one in power takes seriously. Maybe the relationship is just a bad fit that brings out the worst in both of you.

With apologies to Dan Savage: Why not dump the [malefactor] already?

If it were that simple, you would have by now. Financial dependency is the most common obstacle. Or you’ve convinced yourself it’s not that bad. Or you’re trapped in an abuse/honeymoon cycle: Just as you’re ready to walk, you’re wooed back with a raise, a promotion or comp time (which you never seem to be allowed to take). Maybe you believe you’ll never do better, with your outdated skills and skinny résumé.

Here’s the thing: You can have many jobs — even many careers — in a lifetime, but you get only one mind. Once you’re driven out of it, it’s awfully hard to get back in.

If you haven’t already, try simply asking for whatever would make your job bearable: telecommuting, flex hours, a transfer. If your other options range from “mental breakdown” to “making out with document shredder,” what have you got to lose?

If you’ve tried addressing the source of your misery, or that source’s supervisor (a minefield I can’t possibly navigate here — stay tuned for a future column), and see no change — or are targeted for retaliation — then the toxicity is too entrenched for you to fix. Time for an escape plan.

Quietly line up what you’ll need to get yourself to a better place: training, savings, legal advice. Lean on your personal network for perspective and support. If you feel guilty about leaving others behind, remember that you can’t help them while you’re one of them. Get out, get stable, then throw them a rope.

Even if it’s a struggle to reestablish yourself, I still bet you’ll wonder why you waited so long.

Karla L. Miller won the Magazine’s @Work Advice Contest. Miller, 39, lives with her family in South Riding, Va. For 16 years, she has written for and edited tax publications, most recently for the Washington National Tax office of accounting firm KPMG LLP. E-mail us at wpmagazine@washpost.com with any questions for Karla about work angst. And keep letting us know what you think of her advice.

Know when to walk away — and when to run