So yeah, the actual figures are that 20% of married men and 13% of married women cheat, OP was wildly exaggerating. Unfortunately however, if he's already cheated studies show he will almost certainly do so again.
And of course nobody is really saying they are 100% absolutely definitively sure their husband isn't cheating - and equally of course there is no point at all in worrying about something which can't be proven and which has not raised its head at all.
It's neither naive, nor delusional to think your life partner is not an abusive liar. It's simply the normal, healthy way to think and act.
Some, including OP, are bitterly hoping that every woman is cheated on because that will comfort them. Some are never happy unless others are dragged into the gutter with them.
I've been cheated on and of course there are always signs. I mean always. Unless he has incorporated cheating into your relationship from day 1 and normalised any signs you might see or he is a psychopath who has set out to lie to you specifically everyone - abslolutely everyone - notices something is amiss.
Of course that's not victim blaming, in any way. You may not realise what the signs were pointing to until later. Those who have been cheated on and dumped their ex (as I did) for cheating are particularly attuned to it.
So, always trust your gut, but don't spend any time at all worrying about it if you have not sensed anything to worry about. Borrowing misery from the future is a stupid pursuit.
So don't ignore the signs (unless you plan to ignore them forever and hope he stays, which is your choice of course) and don't ever fret about things that will probably never happen if everything seems ok.
And by the way, one of the signs is he's hiding access to his devices. That's not normal, despite what those who are in favour of cheating will tell you 😉 Normal, healthy relationships mean that you can both access one another's devices at any time - and you generally don't bother to but occasionally it's convenient or useful.
What we can factually say though is that those who smirk "You just never know and can definitely not tell and all or most men cheat" are bitter, unhappy and wish that misery on other women.
Glad we got that cleared up :)