It doesn't matter that it's easier. Honestly.
I'm struggling for an analogy, but if you found a car, you wouldn't steal if, would you? And if you noticed it was unlocked, you still wouldn't steal it. There will be a very small cross-section of people who would have just resisted the urge to steal it but then saw that it was unlocked and couldn't resist the extra temptation, but then those people were always going to steal a car - you don't want them around.
I don't think tech makes it easier to cheat - there might now be private browsing, for example, but there was always the ability to delete your history. There might be apps like Tinder, but there was always places to go to meet people who wanted sex. And for every way that tech seems to make it easier, it also complicates it - you might be able to arrange a meet over your phone now, but there will be a message trail. Your phone will track where you are, too.
The problem isn't tech, as you know, it's that some people dont want to fight temptation. It seems your DH is one of them. You could lock him in a room and you'd still know he was simply waiting for an opportunity.
There are plenty of men who aren't like that. It won't feel like it - making yourself feel that most men are like your DH and will cheat if given the chance is a coping strategy, a way to rationalise staying - but there are lots of men who wouldn't dream of cheating even if it was the easiest thing in the world.
When he cheats, will you leave? Or are you planning to stay anyway? You could save yourself a whole lot of pain leaving now, and ripping the plaster off yourself. You won't be happy waiting for him to do it.