How do i deal with the hurt?

I totally understand why this distresses you. It’s natural.

...but...The optimum outcome for your son is that wherever he is - your house or theirs - everybody loves him. Trying to alter that is not having his best interests at heart.

I have seen things like this play out often and [i]kids see and understand the point-scoring game.[/i] The best response is to say it till you mean it - I am glad my son is in a loving atmosphere even when he’s not with me.

If you are convincing, it will not be nearly as much fun for them and your son will sooner or later get the drift.

As much as you want to smash the screen when there’s a picture of her with both hims...take the high road.

I totally understand as I went through it as well. I remember being out with my daughter and some strange lady came up to us and asked my daughter if she was ok and "Where are your parents?". She then looked at me and ran off embarrassed as we looked like twins. So yeah I get how hurt it feels. Here is the conclusion I came too..........Nothing I can do about it. Her father chose to get married again and she had a right to be with her father. I decided that I was lucky, if this woman cared for my child that was a good thing. I didn't have to worry about her and added bonus she had another adult in her life to turn to if she had a problem.

Block her and ignore her, and live your life

Just accept it!
Seriously!
He's not yours anymore,
you have share the son,
they get to have a life too
and it's not going to change.

Your attitude is the only change that will work.
As long as you allow yourself to get butthurt over every little thing, you'll never have a nice new life whilst looking over your shoulder at these things with dismay and anger.