More than any other sport, golf is a mental game. You gotta have everything else in your life peaceful to be able to concentrate.
When Tiger was living the party-life, with everyone applauding and adoring him, things were good in his mind. After “That Night”, he knew his marriage was doomed and that the public saw his image was a fake. That messes up a man’s mind real good.
Perhaps not surprising the best golfers have a stable domestic life?