The aim of this research is to examine the impact of vigilant, devoted, and self-sacrificing personality styles on intimacy (engagement, communication, shared friends) among young adults in romantic relationships (dating/married). A total of 1000 respondents aged 20-40 years old completed questionnaires on personality styles (Personality Self-Portrait) and intimacy (Personal Assessment of Intimacy in Relationships). Data analysis using Structural Equation Modeling (SEM) shows a significant impact of self-sacrificing personality styles on engagement (γ = -0,511, p < 0,01) and communication (γ = -0,361, p < 0,01). There are also significant influences of vigilant (γ = -0,225, p < 0,05) and devoted personality styles (γ = 0,132, p < 0,05) to shared friends. The impact of self-sacrificing personality styles indicates the importance of both parties’ involvement in influencing their relationship. Besides, being too sensitive (vigilant personality styles’ characteristic) and having a sense of comfort in relationships with others (devoted personality styles’ characteristic) could influence how individuals engage in social relationships outside their romantic relationships.