Ex girlfriend

I'm in a LDR and my boyfriend is good friends with his ex girlfriend. He hasn't really spoken much about her because well she's an ex and we are trynna focus on the future. Anyways he knows that I still don't trust him on that and It still bothers me because

1. I've never met her

2. sometimes he goes over to her house without letting me know.

3. When my friends snoop around and they ask her if her and my boyfriend are still together She still saying yes. But when I ask him if she still in love with him he says no.

Anyways I just don't know what to do or if I should keep being upset about it or take it slow and trust him and believe they are nothing.