I'm going to tell my boyfriend I don't want him talking to his ex wife
Why don't you want him talking to her?
I don't want him talking to her because of her appearance.
It's not nice to try and tell someone who to talk to. It's important to trust your partner in relationships.
But she always dresses provocatively everytime she comes around.
That is probably what she usually wears. It's still none of your business.