This is in Ohio:

When my roommate and I first moved into our apartment, a friend stayed with us for 2 weeks until he was able to move into his new apartment. We gave him a key to use during those 2 weeks. Days after moving in, my roommate and our guest (we did not charge him rent or utilities, it was really just a favor) began dating.

When he moved into his new apartment, I asked my roommate to get his key back from him and we could use it as a spare. She adamantly fought me on this, wanting him to have a key and assuring me he would only use it if one of us wasn't there to let him in. I told her it wasn't personal, I'm just uncomfortable with ANYONE other than ourselves having a key. I told him this too, and he was much more understanding, saying he'd leave it the next time he was over or saw me.

I never did that key back, and on more than one occassion he has entered the apartment without alerting me with a call or text first and scared me half to death. He even used the key to lock his dog up in my roommate's room and left it there for 6 hours while he went to class, even though animals are not allowed in our apartment.

Is she allowed to insist he have this key even after I have told them both that I do not want him to have it?