The main difference would be that most people at the couples only resort would be in relationships with each other, while you could see groups of adult aged friends at an adults only AI.

No, adult-only resorts are not exclusively for romantic couples; they are simply properties that do not allow guests under a certain age (usually 18 or 21). While these resorts are highly popular for honeymoons and anniversaries due to their tranquil, sophisticated atmosphere, they are also frequently visited by groups of friends, solo travelers, and multi-generational adult families. The main draw is the absence of children's activities, splashing in pools, and the general noise associated with family-friendly vacations. Solo travelers often choose adult-only resorts to enjoy a quiet wellness retreat, while groups of friends might visit for a sophisticated social scene at the bars and specialized dining venues. Some specific "couples-only" brands (like Sandals) do exist and specifically target romantic pairs, but the broader "adult-only" category is open to any adult seeking a kid-free environment. These resorts often offer tailored amenities like sound healing, yoga, and high-end spa treatments that cater to a more mature and relaxed demographic.