You don't, but if she is then that is her problem. It is your ex-girlfriend, you should have moved on.
If she tells you.
She asks your friends how you are doing, if you are seeing anyone and if you ask about her.
don't do it.
If you wanna know then just ask her. She might be honest or if shes lying then u would know.
Tell her that you still have feelings for her and you know she does too. silently walk away. if she actually loves u she WILL come back. and that last answer was so mean.
he is simply confused
say how much you love her
if they have a lonely look on there face but when hes near she tries too look good
there is nothing you can do
If she keeps eye contact or if she lets you know... maybe if her best friend tells you, you'd know the truth... but for now, just ask her or tell her
Because he still loves her and because he never really has forgotten about her.
You can maybe tell him about how you feel like when your with him how happy you are and how you feel safe with him