He's still texting his ex wife

So I have been with my partner 3years now, and he is my soul mate.

But he still texts his ex wife every day, I know its because of the kids and I'm fine with that.

But with every message that come through he hides it, apart from today I saw over his shoulder.

His still calling her BABE!!

and when I ask about it he said it didn't say BABE, and when I ask to see it his deleted it!!!

WFT!! what do I do??? Need help.