Does he still care for her?

An ex girlfriend texts a guy who has a girlfriend. It’s been a couple of years since the ex and guy have spoken. She ends up saying I have missed you and says she wants to see him in person. His response is we will see. She sends back I know you want to see me too but he doesn’t send anything back. Should his girlfriend be worried? Does a man still secretly care for his ex? Her saying I know you want to see me too but him not saying anything back is weird. How come he didn’t say back I don’t want to see you?