Should I let it go

Been with bf for half a year we’re good together first relationship where he treats me right has never cheated or anything but I saw he downloded tik tok n looked up “big booty”. I kinda got mad bc that’s lowkey disrespectful to me n he did apologize cried all night n promised it would be the last time doing that he even deleted his account n the app. Should I forgive him n let it go or leave.. I’ve gotten hurt bad before so that’s why I’m kinda scared now to stay I feel scared I told him but he said he would never cheat or hurt me that that was a mistake..