When honesty isn't the best policy: The times you should lie to your partner.

We know, honesty is the best policy when it comes to relationships.

If you want to flush your partnership down the toilet the quickest way possible, start lying to them and keeping secrets. See how quickly it catches up with you.

However, in the quest for all-consuming honesty, sometimes people’s feelings and the intention behind your words in the first place, get overlooked.

Listen: We’ve all lied to our kids. (Post continues.)

With that in mind, we spoke to a psychologist willing to give you a pass on some of those teensy weensy white lies and secrets kept that do more good than harm.

Keep in mind this isn’t an all-access pass to Liarpalooza – context is the key. But here are the times you could, and possibly should, lie or withhold the truth from your partner:

When you’ve been hit on by a stranger.

You’re in a committed relationship and just happen to be looking mighty fine as you walk into a cafe. A stranger tries to charm you and maybe even makes a move, and you politely decline.

Sydney-based clinical psychologist Stephanie Allen from Life & Mind Psychology, says this is not a story worth regaling to your significant other.

“You’ve got to ask yourself what is there to be gained by telling them the information or what are the consequences if I don’t tell them this information,” Allen says.

Conversely, think about what the potential harms are if you do tell them.

“Why would you tell them something like that when they’re just going to get upset about it for really no reason?”

“Ask, ‘is keeping this information to myself something that in my wisdom I think is for the benefit of our relationship?’ Then it’s a carefully thought-out decision.”

When you’ve overheard something mean.

If you’ve noticed they’re getting trolled online for a social media post or overheard a mean comment from an acquaintance at a party, it’s not worth opening your mouth about it, says Allen.

“If it’s their close friend then that’s different,” she adds. But if your instinct is to tell your partner about a stranger’s words just so they can defend themselves, ask yourself why it’s worth upsetting them in the first place?

When you don’t like their family or friends.

Your partner’s family is well, annoying. Actually not the whole family, it’s really just their sister. She complains a lot, is often a bit rude to her mum and has a habit of turning every conversation into one about herself.

You don’t want to spend any more time with this woman than you have to. So should you tell your partner?

No, says Allen. This is a moment to reflect on what you’re willing to do for your partner and when you’re willing to put their needs above your own.

"If there's nothing in particular that they've done and you just think, well they're not my cup of tea... I don't think you'd speak up. Being in a partnership means you don't always do things that just you want to do. You need to balance your needs against theirs."

And if it's not that a friend or family member is weird, but otherwise harmless, and they're in fact behaving in a way that's harming you or your partner - like constantly borrowing and not returning money? Well, then, Allen says it's a good idea to talk to your partner.

"It depends on why you don't like them and what you want from your partner. Is there a way you can work it out and you can problem solve."

When you've splurged on a new pair of shoes.

This is one most of us are guilty of. There was a dress or pair of shoes you just had to have, but you know their slightly exorbitant cost will draw some criticism from your partner.

Steph says, in this case, it's okay to keep the price tag to yourself.

Same goes for that cut and colour. Some people (and we're generalising here, but mainly men) just don't get hair. They don't understand how the bill for your 10-weekly appointment could possibly come to $180 and react accordingly. Better just to keep that number to yourself.

However, Allen warns against making this a pattern of deceit.

"If you're bean-counting together and saving for your next holiday and then you go and spend $1000 on clothes, that's not very fair. That's not what we agreed."

When you've already watched that episode.

It's been referred to as "cheating", but really, viewing alone an episode of the TV series you're currently watching together isn't a big deal, says Allen.

"If your partner goes 'let's watch the next episode' and you say 'oh great' as if you haven't watched it, when you've watched it three hours earlier - that's a white lie."

"Is that going to destroy your relationship? No. Just as long as you don't do it all the time."

"That's a good question to ask yourself (in all cases): 'is lying about this potentially destructive to my relationship?'"

When you know exactly where their car keys are.

They're frantically running around the house looking for their wallet or car keys and ask you if you've seen them. You know where they are. You always know where they are. Because this isn't the first time they've misplaced something. In fact, they've come to rely on you to always know where they've left things.

So this time, feel free to answer, "Nah babe, haven't seen them."

Allen says this is actually a compassionate thing to do.

"You're being kind in the sense that it's more helpful for them to take responsibility for their own belongings and that it's not always left up to you."

When they've gone to all the effort of cooking/buying you something nice.

That old saying rings true: it's the thought that counts.

If someone has gone to all the trouble of cooking you a nice meal or buying you a carefully picked out present, now is not the time to crush them by telling them it tastes awful or isn't what you wanted.

Allen says here, you can get around outright lying, by complimenting and recognising the intention, rather than the result.

"I don't think you'd say 'oh, this is the best thing I've ever had' because that's really not genuine. But you'd thank them for the meal," she says.

'But what if I have to eat this awful meal again?' you scream. Chances are, your partner will run the dinner plans by you when they cook. Next time they suggest the eggplant carbonara again, you just suggest something else. Solved.

And finally...

Allen says if in doubt, ask yourself why you're lying. If it's there's a not-so-altruistic motive or keeping the secret could be harmful, then you're best to spill. But if you know in your heart it's harmless, well, here's our blessing to fudge the truth a little.