In the poem "Sex Without Love" by Sharon Olds, who is the speaker and the audience, and what is the rhetorical situation?

The speaker in this poem does not define themselves at all. We might assume that it is Sharon Olds herself. All we know about the speaker is that they are confused by, and then grudgingly admiring of, the people who are able to have "sex without love," as the poem describes. We can infer from this that the speaker is not somebody who has ever been able to do this. They associate sex with love; in this poem, they determine that those who are able to separate the two are the true "pros" or purists, recognizing that their lover is not a necessary part of their own pleasure as such, and that ultimately, they are "alone," striving to reach the highest pinnacles of ecstasy as an individual act.
The audience is not defined in the poem, either. Because the subjects of the poem—those who are able to have sex without love—are defined as "they," we can assume that these people are separate from the intended audience: the speaker is musing, either to themselves or to others who are in the same situation that they are in. The audience is other people who look with confusion and potentially admiration upon the "true religious": those who are capable of making love to people they do not actually love.
The situation described, then, is one in which people are capable of "gliding over" others in pursuit of pleasure without actually knowing these people, let alone loving them. They are able to "come to the God" without any concern for their lovers, knowing effectively that they are "alone" in their pursuit of their own pleasure, a quasi-religious experience.