In the arena of art, it is not uncommon to find great writers, composers or painters who suffer from chaotic personal lives (e.g., lifelong alcoholism, addiction to prostitutes, stormy marriages and affairs), but it seems that most of the biographical sketches of great mathematicians I read portray their lives as peaceful in general.
A counterexample I can think of is Alexander Grothendieck, who estranged his wife and children, seeing other women while married. I understand that the criteria I'm setting is quite vague, but I suppose the example serves an illustrative purpose.
What are some other examples of mathematicians or scientists who led tumultuous private lives?