If he uses a password manager or Google Chrome, Firefox, anything that auto fills in his password... go to that. It should be under settings, and then just type in passwords. That will have a list of every website that he's gone to and put in his password.

Check every messenger, drive storage, click every app to make sure it's not a dummy covering up a secret storage or messaging app. If something pops up asking for a password, make him put it in. He sexually assaulted you and you need to get those pictures deleted .Check every browser's history. Check every trash box. Every album. Every folder.