Driver not on my policy in fender bender. Legal fault is questionable. Other person didn’t show proof of insurance (RI).

My partner drove my car yesterday to work. He is not listed as a driver on my policy which, yes I now know is stupid. Here is what I was told:

He was backing out of a parking spot. He saw a car zoom by going forward behind him, and saw no other cars coming, so he proceeded to back out of the spot. Car #2 backed up really fast, and they collided. He has a witness to corroborate this.

My car has barely noticeable scratched paint on the rear passenger corner (and I’m honestly not sure it wasn’t already there!) Car #2 has a rather sizeable dent in the side of the car, with a streak of paint that is NOT the same color as my car.

Supposedly Driver #2 admitted fault verbally, and wanted to exchange info and call the police. Police did not come, but told her she could come down and give a report if she wanted to have it on record. Partner gave her my insurance info, and he got her license, plate #, and registration info, but even though she “has insurance,” he somehow failed to obtain this information and it wasn’t given. Again, stupid, yes I know.

My questions are:

1. Who is legally at fault?
2. Should we also report to the police?
3. Is this potential fraud?
4. How is this going to affect my insurance and/or me financially?
5. If Driver #2 isn’t insured, does that affect things?
6. If I add my partner to my insurance now, is that going to look sketchy if a claim is filed?

TL;DR – My partner got in a fender bender while driving my car. He is not on my policy and I’m not sure who is legally at fault and if the other person is even insured. How can I protect myself?

Thank you!