I'm sorry for hurting you.
but
I'm sorry about John['s] hurting you/I'm sorry that John hurt you
(note - you wouldn't say
I'm sorry about my hurting you
). You
could say
I'm sorry about hurting you, but I think that version is probably less common; to my ear it puts some emotional distance between me['I'] and you;
I'm sorry for hurting you shows real regret/remorse, and 'about' in that context implies 'but I had to and I'd do it again in the same circumstances' - it's a 'political' sort of regret.
Of course, there's another sort of 'sorry for', that isn't relevant to contexts with a gerund (such as the ones I've given):
I'm sorry for you.
b
PS

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