Classical Arabic poetry often uses a visible object to communicate something intangible. Here thiyāb literally means garments, but the context of intimate attachment and parting gives the image the force of two lives becoming entwined and then separated.
The contrast between thiyābī and thiyābiki assigns the garments to both parties, so that the bond is visualized as a shared entanglement. Instead of stating an abstract verdict about love, the poet invites the reader to picture a concrete action.
Visible imageFigurative sense
Two sets of garments mingledCloseness and attachment
Drawing garments apartBreaking off the relationship
The garments slipping freeCompleted separation