Cats like to sleep next to their owners mainly because it provides them with a sense of security, warmth, and comfort. Sleeping close to a trusted human helps cats feel safe from potential threats, as they are vulnerable when asleep. Additionally, cats seek out warmth, and the body heat of their owners offers a cozy spot, especially when it's cold. Cats also mark their territory by sleeping on or near their owners, showing affection and reinforcing their bond. This behavior can also be a sign that the cat loves and trusts their human, enjoying their companionship and feeling relaxed around them.