Young, maybe? Age does seem to mellow us. Hell, I'm living peacefully with an ISTJ, something I know I couldn't have done 10 years ago!(And for those of you clever enough to catch the omission, I have personally known two other INTJs in my life, and they were both woefully underdeveloped, bitter little people.)
I lived alone for years and had very much the same reaction you describe. I was never bored, rarely lonely and felt very much at peace. I do really well on my own, I still think of it as what feels 'right' or 'natural'.