You are correct in identifying that the silken tent, with its strong, central cedar pole and its many ropes holding it in place, acts as a powerful metaphor in this poem. The tent both stands for the speaker's beloved, but also critics argue that it is representative of the art of the poet. The many ropes that are described in this poem have the impact of holding the tent in place and acting as a counterbalance when the wind threatens to pull too much on one side. The tent is balanced, but although it is "strictly held by none" of the ropes in particular, the many ropes are revealed to represent the "silken ties of love and thought," as the following quote makes clear:
Seems to owe naught to any single cord,
But strictly held by none, is loosely bound
By countless silken ties of love and thought...
The ropes therefore represent the many relationships, cares, and concerns of the world. It is important to realise that in the poem as a whole these can be both negative and positive. The tent is so perfectly balanced and the cedar pole so strong, that even if one of these ropes pulls very strongly, there is another rope on the other side that will help the tent to balance. The "silken tent" therefore acts as a powerful metaphor of how one should live one's life and conduct one's personal relationships, ideally being so balanced that even if there is one pull that is so strong that it threatens to overturn one's stability, there is enough support from other relationships to balance out.