This is what's called a “rebound relationship” and they often don't last long. But at least in this case it sounds like you're both rebounds for the other, so hopefully no hurt feelings here. Meet with your ex if you want to. Just don't get back together until you've totally resolved what broke you up in the first place. This new “relationship” doesn't sound like it's going anywhere anyway. So do what you like.
I would tell her that you’re reporting the sexual assault to police. If she is insistent that you don’t do that, you have your answer
This is what's called a “rebound relationship” and they often don't last long. But at least in this case it sounds like you're both rebounds for the other, so hopefully no hurt feelings here. Meet with your ex if you want to. Just don't get back together until you've totally resolved what broke you up in the first place. This new “relationship” doesn't sound like it's going anywhere anyway. So do what you like.