i think that if you really liked her you would consider asking her if she is in a relationship.
Ask around. Someone knows.
Ask her.
Mom, Dad, I'm seeing someone. This someone is very special to me.....
What no
tell them are you seeing someone if they are then dumb them and say you will never see them again
You can't. Unless the person is your own child, you cannot tell somebody who they can & cannot see. That's being petty & selfish. If you're trying to stop someone from seeing someone else because they're being harmed or you feel they're putting themselves into danger, you can contact authorities & tell them you suspect that the person needs help.
talk to her. see how you can help repair relationship, OR confront and ask why she is seeing someone else and tell her how you feel about it
when they call you. when they ask to see you. when they look into your eyes, and you get that feeling. when they ask your friends about you. when they get jealous seeing you with someone else. the list goes on.
You should dump him, but do it to his face and tell him that you deserve better.
tell quickly ......... otherwise its too late
When someone says they are seeing someone it means they are dating.
Dating is more casual than seeing someone. Seeing someone suggests that there is a relationship either beginning or in progress that is exclusive. You can date several people, but when you declare that you are seeing someone, it's a declaration of a commitment.