TWO. FUCKING. SPACES.
Also, punctuation goes inside quotation marks.
I’m getting that sense of obsessive mantra, S, that indicates a control thing. The screw doesn’t want to be tighter, so stop pulling the wrench in that direction. They used to say playoff A-Rod came about because he’s such a perfectionist, that his obsessive mantra of batting instruction overtook his sense of feel. It indicates you don’t trust yourself, and becomes a self-fulfilling prophecy. You need to BECOME THE CENTAUR. Or go cruising for chicks with Swish.
And if you’re going to be anal, at least be correct about it.
Most of the definitive guides are (at best) agnostic on double spaces after the period. There was little reason for them after the invention of the typewriter and there’s even less in the age of computers.