Around a fifth of women say how confident they feel about their body has a constant impact on their sex lives, research has found.

A similar proportion worry a “great deal” about what their partner thinks about their body, according to YouGov’s body image study.

Some 18% of women and 10% of men say how secure they feel about their body constantly affects their sexual relationships, the survey found.

Women were more likely than men to feel pressure to look a certain way and worry about their partner’s view of their body, with younger women particularly affected.

Overall, 61% of UK respondents said that their feelings about their body affects their sexual relationships, with one in seven adults (14%) saying this is constant.

And a quarter said their sex lives were occasionally affected by these feelings.

YouGov surveyed 2,271 UK respondents aged 16 and over in February for its body image project.

The results, shared with the PA news agency, show 21% of women and 11% of men worry a great deal about what their partner thinks of their body.

A further 43% of women and 39% of men said they are “somewhat bothered” by this.

Three in 10 women under 40 said they are very concerned about their partner’s views on their appearance.

As people get older they are less likely to report their sex lives being affected by body confidence issues, although the gap between men and women persists, YouGov found.

Women are more likely than men to feel that physical appearance matters “a great deal”, and feel pressured to have a certain body type.

More than half (52%) of women said physical appearance matters a great deal, rising to 61% of younger respondents aged 16-24.

Some 39% of men felt this way.

Half of respondents (51%) also felt pressured to have a certain body type – with women significantly more likely to feel this way than men (61% v 40%).

Younger women were significantly more likely than men of their age, and older women, to report feeling a great deal of expectation to look a certain way.

Ammanda Major, head of service quality and clinical practice and counsellor for 25 years at Relate, said women are exposed to unrealistic expectations online, on television, and in films, advertisements and pornography.

The message they take away is that they “need to look a certain way in order to either keep or attract a sexual partner”.

The sex and relationships therapist told PA: “People are consistently surrounded by images of perfect bodies, perfect everything in the media, in films, on social media, and it can be an insidious thing – people perhaps not so aware that gradually they are starting to form a belief that you’re not OK unless you are doing everything you can do to look a certain way.

“And actually, I think that’s what becomes the pressure – people telling themselves that they’re not good enough because they don’t look like stuff they are seeing on social media or wherever.

“So I think there is something around, you know, standing back and learning to love that person in the mirror, because that person in the mirror is very likely absolutely fine.”

She said communication within couples to provide reassurance, and counselling in some cases, can be helpful.

The research also found that 87% of respondents believe that those who are better looking are treated more favourably because of their good looks.

And two thirds (68%) think that a person’s looks make a difference to their personality, with younger respondents less likely to feel this way.

YouGov project manager Milan Dinic said the survey suggests that women feel body image pressures more acutely than men, with very few feeling no pressure to look a certain way.

He said: “Generally, the vast majority of the public think that how someone looks matters a lot in today’s society, and that those who are better looking are treated more favourably.

“However, while those in their teens and early 20s are more likely than those in their 60s or older to say that physical appearance matters a great deal in today’s society, they’re less likely to think that looks impact people’s personality.”

Tom Madders, director of campaigns at YoungMinds, said body image concerns can have a significant impact on the mental health of young people throughout and beyond puberty.

He said: “If you’re worried about how you look and it’s affecting your mental health, be kind to yourself and try to remember that images online are often digitally altered to make them look ‘perfect.’

“It’s also a good idea to spend time with people who make you feel positive about yourself.

“If you’re really struggling, talk to someone you trust, who can provide you with reassurance or give you extra support – this could be a family member, friend, or even your GP.”