When is it too much?

He and I started dating at the end of December.
It's now June.
I think it's safe to say
that we take each other seriously.

My ex called.
I am still friends with him.
We didn't end badly, just grew apart.
He knows this.

I have nothing to hide
I talk to my ex right in front of him.
we say things like,
"How are your parents?"
"How are you?"
"How is your girlfriend/boyfriend?"

I can't help but wonder.
Is it still unfair?
I put myself in his shoes.
He's done similar to me.
Maybe not ex-girls.
But definitely side ones.
As long as he's mentioned me.
I've not had a problem with it.

So, do I go on that?
Or say something to him?