How to know if boyfriend is cheating

Hi so sometimes I think my boyfriend is cheating without any reason to think that he doesn’t hide things I know all his friends ( literally All males )

I know all his passwords and have access to his phone and socials ( all of them ) but the only girl (besides me ) he has added is one of his old friends( don’t talk to them anymore ) mom ..

I do trust him but sometimes I do think about it

What’s the signs of when somone MIGHT be cheating even if they say they will never ( never say never )

But generally speaking we’ve been together for almost five years and we are abit long distance I have access to his location 24/7 ( not a stalker type he has mine too )

I’ve also checked his text messages

All he has is family members ( like aunts and cousins ) added

Photos are just all of me basically

We are both young so generally speaking what do you guys think ? I’ve asked. Him before and he said he never did and never will and that the loves me. Truely I just need constant reminder that he loves me ( since I do deal with anxiety and other things ) r