Firstly two previous posts on this blog seem relevant:
January 2013 and January 2010
Perhaps these say more than than anything else that I can add.
However secondly I would add that had Mandela not did what he did as regards working towards reconciliation, the risk of much internecine or civil warfare and killing between black and white South Africans would have been huge.
That he avoided so much strife and saved so many lives are surely matters to to be remembered and celebrated at this time.
The biblical story of Jesus meeting the woman at the well and asking her for a drink seems to me to be spot on as regards Mandela's private life. The woman having had I think more husbands than Mandela had had wives, was after letting Jesus drink as I recall forgiven and told to go away and sin no more.
The open hearted provision of a drink to a thirsty man was essentially more important than the upheavals in her private life. So it is in my view with regard to the late Nelson Mandela's private life.
Essentially he gave all South Africans water to drink in equal measure at a time when drinking water might by analogy have been said to be far more available to a small percentage only of the South African population. Almost miraculously in my humble opinion his deep insight and actions in public life saved the country from dreadful civil war and fighting and for that he was indeed a great man.