The Fundamentals of Sex

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Positive body image strengthens sexual assertiveness and relationship satisfaction.

Body image impacts sexual functioning more than BMI or body size.

Assertive expression of desire predicts greater relational and sexual fulfillment.

New research provides key insights into what partners need when it comes to more pleasurable sex.

General couples/relationship therapists observe common relational and systemic dynamics that affect most romantic relationships, such as:

Communication patterns

Attachment styles of each partner

Past traumas (including sexual trauma, childhood trauma, and domestic violence)

However, another critical factor shows up frequently in individual and partner therapy with certified sex therapists, which can be frequently overlooked by general couples therapists and/or a romantic partner: negative body image.

Many people who struggle with sexual connection, low desire, or relationship satisfaction may not be struggling with the love they feel for a partner or the level of commitment they have to their romantic relationship(s). What they may secretly be challenged by is the lack of comfort and safety they have in their own skin.

A negative body image can come with a host of symptoms, including avoidance of:

Expressing desire to a partner, and/or

Communicating boundaries

In a recent 2025 study in Behavioral Sciences, Rizzo et al. examined how body appreciation, sexual esteem, and sexual assertiveness influence relationship satisfaction. They found that the way people feel about their bodies and whether this impacts their communication contributes to how they show up in their sex lives, which in turn can affect their romantic relationship(s) as a whole. These findings align with what the Sex Esteem® framework aims to improve in somatic sex therapy sessions.

The Study: Who Was Included and What Was Measured?

Rizzo and colleagues recruited 473 Italian adults (50.1 percent men, 49.7 percent women; ages 18–49) who were currently in heterosexual romantic relationships.

The participants completed four self-report assessments on:

Body appreciation (Body Appreciation Scale-2)

Sexual esteem (Sexual Esteem subscale of the Multidimensional Sexuality Scale)

Sexual assertiveness (Sexual Assertiveness Questionnaire, focusing on initiating sex and refusing unwanted sex)

Relationship satisfaction (Dyadic-Familiar Relationship Satisfaction Scale)

The researchers then used structural equation modeling (SEM) to test how these key pieces were connected in those relationships.

Sexual Confidence Is Not Enough Without Clear Communication Skills

Rizzo et al. discovered that when individuals felt more accepting and positive toward their bodies, they also were more confident sexual partners. However, the correlation the authors reported was: “Sexual assertiveness, but not sexual esteem, was positively associated with relationship satisfaction." In other words, a person having body positivity on its own isn’t enough to improve one’s sex life. It was only when the subjects felt more confident enough to take actions like initiating sexual activity, communicating their desires, and clearly accepting only the sex they wanted that the subjects reported improvement in their sexual and romantic relationships.

The difference between sexual esteem on its own versus when it is combined with sexual assertiveness is shown to be critical in this study and in clinical sex therapy.

Internal confidence is great, but alone, it doesn’t equal relational happiness.

In a somatic sex therapy clinical framework, two key cornerstones are confidence and communication skills. As confirmed in this study, what matters most to adults in a sexual relationship is how their sexual esteem is enacted through clear, confident communication skills followed by actions. Without clarity on what is wanted in a sexual scenario and the limits of what will be a consensual shared sexual encounter, partners frequently find themselves falling into patterns of:

Avoidance (experienced as personal rejection by a partner)

Compliance (resulting in duty sex)

Unspoken (or passive-aggressive or aggressive) resentment over time

Potential non-consensual and/or coercive sexual encounters

Further Research Results on Body Image and Sexual Function

The previous study results are consistent with prior research on negative body image/low self-esteem. A 2023 study in the Annals of the Academy of Medicine, Singapore, found that poorer body appreciation was significantly associated with female sexual dysfunction in a questionnaire given to 514 sexually active young women (21-35) (Husain et al., 2023).

The Fundamentals of Sex

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Find a sex therapist near me

In past studies, researchers focused on how being overweight or underweight as a physical factor can impact people’s sex lives. However, similar to the previously cited study by Rizzo et al, Husain et al. found that a negative body image had a strong impact and relation to sexual dysfunction, unlike BMI (body mass index).

Specifically, lower body image and lower self-esteem were linked with poorer scores on the Female Sexual Function Index, whereas BMI categories (e.g., overweight) did not show a strong association with sexual dysfunction outcomes. This suggests that how a person perceives their body matters more than people may think.

How Negative Body Image Intersects With Sex Therapy Skill-Building

Both of these studies, along with sex therapy clinical experience, illustrate that when a partner feels disconnected or negative about their own body image, it is usually combined with less-than-optimal communication skills. Sexual avoidance, difficulty initiating, or the lack of communicating preferences can slowly destroy intimacy over time.

Rizzo et al. (2025) remind us that relationship satisfaction is not built on sexual self-esteem alone, although it is helpful. It is the combination of the ability to use that internal security for authentic relational clarity in communication with a sexual partner. Having the courage to say “I want you,” “I don’t like that type of touch,” or “This stimulation feels good” requires a Sex Esteem® confidence-communication skill, and trust in one’s partner to listen without defensiveness, minimizing, or gaslighting. Therefore, improving intimacy may not only include improving or maintaining one’s positive body image but also gaining verbal and non-verbal techniques to express the nuances of what one truly desires and listening to a partner’s needs and wants without feeling pressure to immediately consent, people-please, or enact a sexual scenario.

Positive sexual self-esteem is one cornerstone of gaining authentic Sex Esteem®. It is the development of one’s sexual voice along with improved communication techniques, as the research above suggests, that helps to build improved relational and sexual satisfaction in relationships.

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Rizzo, M., Matera, C., Caso, D., Donizzetti, A. R., Grano, C., Nerini, A., & Rollero, C. (2025). Satisfaction in romantic relationships: The role of Body Appreciation, sexual esteem and sexual assertiveness. Behavioral Sciences, 15(12), 1730. https://doi.org/10.3390/bs15121730

Husain, F. S., Lulla, D., Tay, T. K., Lee, J.-J. M., Dhaliwal, S. S., & Ang, S. B. (2023). Association between body mass index, body image and self-esteem with sexual function: A survey of young women in Singapore. Annals of the Academy of Medicine, Singapore, 52(4), 190–198. https://doi.org/10.47102/annals-acadmedsg.2022358

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