My friend the sociopath

From a recent comment to an older post:

I have been best friends, and occasionally romantically involved with
a sociopath over the last 10 years.
He is the father to both my children.

I have always approached our relationship with honesty in everything.
I do not project my needs on him. I see him for what he is and I accept it.
I am bipolar. His limited depth of emotion has never bothered me too
much. I'm used to it from everyone in varying degrees.
How he thinks and feels....That's just how he does things, it's him.

What makes our friendship work, is that we both understand and accept
each other for what we are. We find things to base our friendship on
that aren't the traditional source of "love".
I value him. I enjoy how he thinks, how me moves.
I enjoy how he challenges me to think 5 steps ahead.
I have things I am better at than him, so I still have some power in
our dynamic, but he still wins most of the time. and that's okay with
me.

He enjoys how unpredictable and chaotic my emotions, and thoughts are.
He appreciates the effort it takes, and my mastery of reigning myself
in. Even when I control myself to the point that most people don't
recognize when I'm bothered, he still picks p on my subtle cues.
We both struggle with blending in. We both struggle with this weird
sense of detachment from reality, where normal people march around
like robots.

We both have violent impulses with atypical motivations for not acting
on them. He finds violence to be inconvenient. I find it messy.
Both of us find those motivations to be much stronger than any guilt
we might have.

He grounds me when I get too whimsical.
I push him to strive for bigger, less obvious goals.
We both parent our children in a way that nurtures and challenges them.
They feel safe, but they are pushed to grow as people.

Even in bed we compliment each other.
He sometimes enjoys being violent, and I enjoy fighting him.
It's exciting to be challenged.

In everything, we push each other to think, to win.
And it's not clear very often who will win.

At the same time, I recognize what he is.
I know he needs space when he's bored.
I know when I am not entertaining enough for him, and I'm not offended
by it. Frustrated maybe, but that's just because I enjoy his company.
He always comes back eventually though. In the meantime, I am just
fine on my own. I don't like most people, and I prefer to be solitary
anyway. He is one of maybe three people, I actually want around.

Our relationship isn't built on love, it's build on mutual
understanding and acceptance. We work, because we've both decided that
the other one is acceptable as is. We don't demand more than the other
can give.
Anything else would be selfish.
To expect him to "love" me, would be not to know him at all.
That seems like a gross and lonely thing to do to him.
It wouldn't be fair.
He says he loves me, like one loves a favorite T-shirt.
I appreciate that.

TLDR; My motivation for being friends with a sociopath is that there
is mutual understanding and acceptance I have never gotten from anyone
else. He is him and I am me, and that's good enough.