So my boyfriend has a 'best friend' who he's known for forever! And she's a girl. Now that doesn't bother me but this girl is friends with my boyfriends ex. So every time she's over or talking to us

It's about his ex (who he went out with for over 3 years & they have known each other for over 5, they don't talk anymore but still) . Anyways she says Things like 'She's sleeping with so many guys' & 'she won't stop talking about you'. This makes me so god damn upset. And I don't think I'm over reacting about it? It's a little rude right?

Also she lives in her own house and she's renting a room and my boyfriend is looking for an place to live in. She said he should come live with her and I wouldn't be too worried about that but

1. My boyfriends ex is crazy and as soon as she finds out my boyfriend is there she will come over.

2. My boyfriends 'best friend' literally said to me while looking me in the eyes "but I don't want any girls living with me".

I found it so fkn rude.

3. If his ex does come over and I'm not there I would be so scared that she would try something with him. He would push her off because he's the most loyal, loving boyfriend ever but still.

It's hard to say things to my boyfriend and I'm just wondering on advice as to how I could say something to him?