How Can I Stop This Girl From Coming To My House

There is a course mate of mine. We were close friends in school. So there is this day she followed me to my home (because I don’t live in the hostel, I rented an apartment outside).
I was so hungry so she decided to cook for me.

After we finished eating, one thing led to the other and we had sex.

This girl is in her early twenties, just like me.

Since that day, she has never let me rest.

We have been having sex and she told me she has a boyfriend.

She comes to my house and we always end up having sex all the time. I

have told her enough is enough but she keeps coming. I use protection, though.

I blamed myself for letting her know my place

How Can I Discard This Girl Totally Because As Long As She Comes, I Will Keep Sleeping With Her?