Having sex in the Oval Office, fine. Just don't expect others to go to prison to protect your God-given "right" to have an intern lick your anus. Ref: Starr Report.
I am not a close student of Watergate but have some acquaintences who have gone the extra mile, including two who actually sat down and read the transcripts of all the tapes. Neither is a professional historian (fairly accomplished amateur historians, however) or a politico with an axe to grind. Both had the impression, which is shared by a number of the published authors on Watergate, that Nixon simply didn't know what had happened. Unless a smoking gun emerges, I will continue to entertain that hypothesis. It's really Occam's Razor: Nixon's mishandling of the whole mess is most simply explained by ignorance. Had he known what was up, he probably could have found a way to cut his losses and contain the damage early.
That leads right back to the big unanswered question: who ordered the break-in, and what was the real target?