Unsure what you mean by "managed". Executives who do coke on weekends usually aren't responsible parents of five kids (work all week and then doing coke on weekends means less family time). Additionally, we hear enough about executives doing coke enough for it to be a pop-culture staple (let alone the associated depictions of narcissism).
Generally speaking, people aren't as clever as they think they are when it comes to hiding their vices, let alone segmenting that part of their lives without some distance from others and a fair amount of dishonesty.
Ultimately, Nick's hedonistic/narcissistic lifestyle was incompatible with being an aging responsible parent of five children. This is a contributing factor as to why Nick was in (midlife) crisis and why he has proven to be so irresponsible. Honestly, even if someone were still in college (or an executive), it would be difficult to recommend that they get into heavy drinking, hard drug use, and casual sex (or hookers), if even for only health reasons. Moving on...
If successfully "segmenting their lives" means "we never hear about [it]", then Nick's biggest crime was getting caught.
I don't think this is what you were necessarily intending to say, but Nick would agree with this sentiment. To Nick's mind, it isn't about what Nick did or didn't do. It is about what "the government" can prove he did.
For example, according to Nick, no one has driven while impaired until they were convicted. The distinction between being legally impaired due to being caught by police and the biological impact alcohol has on the human body (regardless of police presence) is lost here.
To put it another way, Nick seems to think that a tree falling in the woods only makes a sound if convicted in a court of law.
The objective circumstance you refer to runs counter to this mindset. It is a very legalistic standpoint. Inherently both very defensive and very narrow. Nick's is reasoning like the caliber of lawyer he is... and to a man with only a hammer, everything is a nail.