Partners are supposed to tell each other everything - after all, honesty is the best policy.
But aside from hiding an embarrassing one-night stand, your other half may also be keeping a far more superficial secret.
Maybe throwback photos of them gave it away, or a family member dropped a hint, but you have a sneaking suspicion your loved one has gone under the knife for cosmetic enhancement.
More than six million Americans undergo cosmetic procedures every year, and while estimates as to how many hide them from their partners are scarce, one 2014 survey found roughly a third of patients hide what they have had done from their significant others.
With modern techniques, high-quality procedures can be virtually unnoticeable to the untrained eye.
But now, experts have told the Daily Mail that even the subtlest signs of nips and tucks can be identified if you know what to look for.
'In general, it is far easier to hide smaller office procedures like injectables or Botox from your close contacts - but even those can cause bruising or swelling,' Dr Catherine Hannan, a board-certified plastic surgeon based in Washington, DC, said.
'I've worked with enough patients that write off smaller facial procedures as 'allergic reactions' or 'walking into cabinets' and as a one-off it can work. It tends to be less of a reliable cover when it happens repeatedly.'
From barely perceptible changes along the hairline pointing to a facelift, red spots along the lip line indicating injectable filler, to always-perky breasts suggesting a breast augmentation, partners can begin to connect the dots.
Dr Catherine Hannan, a board-certified plastic surgeon based in Washington, DC, told the Daily Mail that signs to look for include a strangely 'frozen' face; breasts that stay perky when lying down; a perfectly symmetrical hairline; a nose with uncanny perfection; and signs of recovery like unexplained hunched posture and fatigue.
Botox and filler
The refreshed glow after a 'spa trip' could be the settled result of strategically placed filler and Botox, leaving the cheeks plumped with barely a smile line in sight. A static face is the greatest tell.
A partner may notice their significant other's face looking strangely frozen or immobile in spots during normal conversation. Their forehead might remain smooth when they’re surprised.
Their cheeks might stay perfectly plump when they break into a wide smile, with no crow’s feet or wrinkling around the eyes. The skin might feel unnaturally firm, cool or smooth to the touch.
Dr Anil Shah, a plastic surgeon based in New York City, told the Daily Mail: ‘Botox has a giveaway. It’s when the brow creates a super arch.’
‘The goal of Botox is to soften facial expressions, not create villainous expressions afterwards. When a partner looks back at their significant other, and now they’re an evil character, more than likely they’re going to be upset.’
The subtle, 'refreshed' look from a spa trip can be a sign of cosmetic treatments: lip fillers may create an unusually plump, smooth pout, while Botox and other fillers are often betrayed by an unnaturally frozen expression, a lack of natural movement when smiling and a telltale stiffness to the touch.
Breast augmentation
While natural breast tissue would naturally relax and spread when a woman lies down on her back, breast implants cause them to remain perfectly upright and perky - hallmark signs of a breast augmentation.
A partner might feel a firm, defined edge at the perimeter of the breast or notice that areas of the skin, particularly around the nipple, remain surprisingly numb to the touch, evidence of the surgeon’s alterations to nerves and the placement of a silicone or saline implant.
Even for people who haven't committed to implants, less invasive breast augmentations can still leave subtle signs.
The concept of a quick 'lunchtime lift' has led to various experiments. While injecting large volumes of standard filler is impractical, newer methods are emerging.
These include using processed donor fat or, more recently, tiny silicone implants that can be injected via a tube through a small armpit incision under local anesthesia. A similar product, Preserve, is available in the US.
While designed to be minimal, it would heal as a small, linear scar in the natural crease of the armpit.
Dr Hannan said: 'Believe it or not, people could inject sterile salt water/saline into the breast tissue to temporarily enlarge the breasts, usually before an event, then the body would absorb the fluid and they'd shrink again over a few days.'
Face lift
To spot a good facelift, Dr Shah said: 'Look for scars in front of your ear; there's almost no reason to have a scar there; 99 percent of the time it means you've had a facelift.
'Clever surgeons are now hiding scars solely in the hair, or making incisions only behind the ear, the part where you put your glasses.'
These scars are expertly hidden, tucked into the fold of the ear or concealed beneath the hairline, making them virtually undetectable in everyday view.
He added that the 'tell' of a bad facelift is a bizarre, stretched appearance. Today's skilled surgeons avoid this by working on the deeper muscular layer, producing a lifted but undetectable result that fools partners.
Dr Hannan added: 'Facelifts, rhinoplasties, eyelid lifts and browlifts cause enough facial bruising and swelling for days to weeks; it would be almost impossible to hide from a loved one in your home.'
If your love interest is newer or you spend less time together, bruises may have faded but some scars will remain.
'Weeks to months later, the scars of a facelift, eyelids or browlifts are well hidden and would be difficult to see except for up close, and the scars of rhinoplasties are designed to be hidden in the nostrils so they will be almost impossible to see for most loved ones,' Dr Hannan explained.
Rhinoplasty
The most subtle sign of a nose job, or rhinoplasty, is not a flawed result of the procedure but rather an uncanny perfection.
A natural nose has soft, organic curves and hard-to-perceive asymmetries; one nostril might be slightly wider than the other or the bridge might have a gentle bump.
Meanwhile a surgically modified nose usually has a ruler-straight bridge, a perfectly symmetrical tip and a scooped profile.
Small, pale scars concealed within the nostrils or across the strip between nostrils are the remnants of the surgeon’s access to the cartilage. The nose may feel unchangingly rigid, lacking the natural slight movement when talking.
Dr Shah said: 'The giveaway is going to be weird shadows, increases and contours. Almost always, this happens from chisels.'
'The new aids of surgeons are using ultrasonic shaping, leading to noses that are almost undetectable because they look so natural.'
Hannan added: 'Weeks to months later, the scars of facelifts, eyelids or browlifts are well hidden and would be difficult to see except for up close, and the scars of rhinoplasties are designed to be hidden in the nostrils so they will be almost impossible to see for most loved ones.'
Hair transplant
Hair transplants, once known for looking 'pluggy,' have evolved in recent years to look more subtle and natural.
The most tell-tale sign is a perfect, uniform hairline, often razor-straight or overly symmetrical, lacking the randomized irregularity of a natural hairline.
Tummy tuck
While minor nips and tucks may be easy to mask, Dr Hannan said 'surgical procedures... that require sedation or general anesthesia, are much more difficult to hide.'
In the days after undergoing a procedure, a partner may not be able to stand up straight if they’ve had abdominal surgery such as tummy tuck or liposuction and could be hunched over for a week or more, Hannan said.
For one to two weeks, they’ll walk and sleep in a permanent stoop to protect tight abdominal incision; unable to stand up straight. Simple movements like sitting up or laughing will be painful; they’ll avoid lifting anything heavy. They may also be hiding drain under their shirt which can result in some stained sheets.
The definitive sign after recovery is long thin hip-to-hip scar positioned low; often just above pubic hairline; meant to be hidden by underwear or swimsuit bottom. It may feel raised or thick initially and a partner would be able to see or feel this during intimacy.
Beyond the hallmark low scar, signs of a healed tummy tuck include unnaturally flat and tight stomach that may look disconnected from upper body; surgically reshaped or high-placed belly button; permanent crease above hip line.
Brazilian Butt Lift
A well-performed BBL aims to leave no visible marks on the buttocks themselves. The most common telltale signs are actually elsewhere on the body.
Look for multiple small discreet scars often resembling freckles or beauty marks with a slight sheen around the hips lower back or crease beneath buttocks.
These are entry points for liposuction used to harvest fat. A partner might also have surprisingly smooth contoured areas where stubborn fat used to be like lower back or thighs which can contrast with newly rounder fuller backside.
The true 'tell' of an unnatural or poorly performed BBL isn't a scar but an exaggerated over-projected silhouette that looks disconnected from lower back often called a 'shelf' appearance.
A skilled surgeon creates a result that flows naturally from waist into hips and buttocks. In months following surgery once swelling has subsided good result should look balanced and proportionate not obviously surgical.
While a partner might be able to conceal the initial recovery which involves avoiding sitting and significant bruising the lasting change in their overall body contour and the presence of those tiny liposuction scars are the most reliable indicators.