Because of his great love for them, Paul makes it clear that his rebuke in his first letter to them (the rebuke of their acceptance of the sin of immorality) caused him pain as well as pain to the church people in Corinth and the immoral man.
Paul uses this rhetorical question to emphasize that neither he nor they would benefit if his coming to them would cause them pain. AT: "If I caused you pain, the only ones who could cheer me up would be the very ones whom I had hurt" (See: [[rc://en/ta/man/translate/figs-rquestion]])