Outdoor couch cup holder options
Compare a resting base with furniture attachments.

Portable resting base
Steadi fits a compatible drink and moves between supported spots. It does not attach to wicker, cushions or the deck.
Arm tray or clamp
An arm tray or clamp depends on the furniture shape and material. Check the exact accessory instructions and whether the furniture maker permits attachment.
Side table
Choose a wide stable top and a height that works from the occupied seat. Ground irregularities can make a good table unsuitable in a particular position.