Gregory's house
At the beginning of the play, Greg says that "I love my... house." Although Gregory does indeed love his house and its furnishings, here he means he loves the essence of his house, which has been created by his relationships and his fond memories experienced there.
Arthur and Perry
Arthur and Perry symbolize the realism of a long-term relationship, with all its ups and downs. Although they do love each other, they also are shown to argue frequently and bicker. As such, in contrast to the relationship between Gregory and Bobby, their relationship is long-lasting and committed.
Gregory and Bobby
In the play, Gregory struggles considerably with his identity, and it seems as though he is trying to find a sense of meaning through his relationship with Bobby. As such, their relationship symbolizes Gregory's failed attempt to find his purpose and meaning without looking inward.
Love
Love is a key motif in this text and can be seen with the focus on three couples. Significantly, Gregory and Bobby are at first shown to be happy and fulfilled, but the cracks in their relationship are revealed as the play continues.
Bobby's blindness
We might see Bobby's blindness as representing his ignorance about Gregory and the reality of their relationship. Similarly, Gregory is unaware of Bobby's actions in the play.