I'm sure i saw a Question about this hadith (or maybe an answer including it) here before.
But the answer is simple this is a Narration from Sahih al Bukhari.
And Abu Huraira (May Allah be pleased with him) didn't change anything (and Allah knows best) but when you read the statement(s) you find out it has two separated parts.
One part where Abu Huraira (May Allah be pleased with him) narrate what he heard from our Messenger (Peace be upon him)
"The Prophet (ﷺ) said, 'The best alms is that which is given when one
is rich, and a giving hand is better than a taking one, and you should
start first to support your dependents.'"
So here at this point the hadith itself ends!
To support this here a couple of ahadith which have the more or less same matn
- From Sahih al-Bukhari narrated by Hakim ibn Hizam (May Allah be pleased with him) and al-Bukhari gives an other chain for this which ends with abu Huraira!
- From Sahih Muslim narrated by Hakim ibn Hizam (also as this Version is in many Hadith collections) (May Allah be pleased with him)
- From Sunan an-Nasa'i narrated by Abdullah ibn 'Omar (May Allah be pleased with both) (This version can also be found in many Hadith Collections).
And what follows must be called saying of a sahabi or fatwa of ijtihad of a sahabi!
And the second part is an interpretation or an explanation (ijtihad) of the saying of our Messenger (peace be upon him) made by Abu Huraira (May Allah be pleased with him):
"A wife says, 'You should either provide me with food or divorce me.'
A slave says, 'Give me food and enjoy my service." A son says, "Give
me food; to whom do you leave me?" "
And this is what he said about
"No, it is from my own self."
And just to support my proof: You find this hadith in Riyadu-as-salihyn of Imam an-Nawawi quoted without the saying of Abu Huraira (May Allah be please with him) which is more or less the same (with a difference order of the sentences) and this fatwa (in Arabic) which goes ahead with my proof, so scholars distinguish between the hadith and the addition, which was ijtihad or saying of a sahabi!
And Allah knows best!