Jamieson, Fausset and Brown on 2 Corinthians 2:5

5. grief ... grieved--Translate as before, "sorrow ... made sorry." The "any" is a delicate way of referring to the incestuous person.

not ... me, but in part--He has grieved me only in part (compare 2Co 1:14; Ro 11:25), that is, I am not the sole party aggrieved; most of you, also, were aggrieved.

that I may not overcharge--that I may not unduly lay the weight of the charge on you all, which I should do, if I made myself to be the sole party aggrieved. Alford punctuates, "He hath not made sorry me, but in part (that I press not too heavily; namely, on him) you all." Thus "you all" is in contrast to "me"; and "in part" is explained in the parenthetical clause.