spider/ant nest

Unfortunately, soil and nutrients within a pot are so limited that even good bugs doing as you describe will eventually grow to the point where the plant will suffer heavily. So, you'll need to mount an attack if you hope to keep the grapevine.
After harvest, pull the plant out of the pot and with a stick poke out as many of the pests as possible, spray with a recommended bug killer, let dry, then repot with some fresh amended soil around the sides and in the tunnel areas. Next year keep the pot off the ground which is usually why most pests want to call it home.