Not all desire for sex requires an explanation. Some desires are simply a matter of attraction, lust, or pleasure seeking without any deeper meaning or motivation beyond the physical act itself. This is true even if there may be social, cultural, psychological, biological, spiritual, or philosophical implications that inform one's approach to sex and sexuality. Desire can arise from a variety of sources including physical appearance, personality traits, body language, emotional connections, sensory experiences, and so on. It can also be influenced by past experiences, fantasies, or expectations.
Not every instance of sexual interest needs to be analyzed or justified with rationales or explanations. There are times when the drive towards pleasure and satisfaction is enough to justify engaging in sexual activity without needing to explore its underlying reasons. When it comes down to it, some people simply want to have sex because they feel like it and nothing else matters besides that fact alone. They do not require external validation or introspection into their motivations to pursue intimacy. In this way, eroticism becomes a pure expression of self-gratification and fulfillment rather than a search for something more profound or meaningful. Of course, it is important to recognize that each individual's experience of desire will differ based on personal history and belief systems.
Someone who grew up in a religious household might view sex as taboo while another person raised in a permissive environment might see it as natural and healthy. Nevertheless, it is ultimately up to each person to decide how much thought and analysis they put into understanding why they find certain types of sex appealing.
Not all desires should be overthought or explained away; sometimes they exist purely for the sake of pleasure itself.