I agree to be vigilant for now.
By the way, my own h did not password protect his phone and after I got suspicious and mentioned his laptop twice, he first of all had it password protected, and then gave me the password, and a couple of years later agreed not to delete his history any more, as he had 'nothing to hide'.
He was doing it though, and for five years, and finally admitted it.
I just say this because although laptops, phones and credit card/bank history details can be brilliant for catching out cheaters, and are clearly the first place to look, sadly with some men (especially clever and confident ones), they wont necessarily give the game away.
Because money can be spent in cash and saved over time for that purpose, or fobbed off as work expenditure etc
phones and laptops can have stuff deleted or selectively deleted.
eg my h's history was clean, but later he admitted just editing it afterwards or using private browsing, and he didnt use his phone at all. He even downloaded messenger each time he needed it and deleted it the same day.
THe good news is that vigilance in my view always pays in the end, and they slip up, if you keep looking discreetly.
And in any case, afterwards it is possible to see that their overall behaviour towards you at the time was giveaway enough that the relationship was in real serious and trouble, at the least.
So my advice would be to say nothing more, accept his explanation, keep looking anyway now and again and have a long hard silent think about the relationship in general, and how much he seems to care about you as a person, regardless.