Not everyone is a cheater. Be careful when you leave one not to think everyone else you meet will do the same thing.
Keep an open mind.
The best defense is when you enter a relationship holding 5% doubt.
I’m not saying you go through his phone, you hire P.I.s you suspect every lateness. What protects you is if you leave that ‘door’ partially open.
Don’t immediately think; “Ah! He’s late! Must be with Slutina!” but keep in the back of your mind the possibility.
Those who are devastated by adultery are those who were sure that it would never happen to them.