My partner has recently started texting a younger work colleague constantly everyday/ night for hours at a time even ending texts with xx, this girl knows who I am and has even seen our son while I've been at his work, I just don't understand why their texting constantly to each other, should I be worried, she doesn't work in same building but visits there occasionally one day when she appeared for the first time she seen me she didn't know who I was when I was standing next to my partner, until she came up close and someone said to her who I was and she went bright red in the face and quickly disappeared, my partner says there's nothing in it when I question him about it, but I just don't understand the texts everyday after working hours