Cheating Fiancé?

So I am in love with my fiancé and we’ve been through a lot together. We’ve been together for 3 years now and I always told him that if he were to lie to me it’d be his choice but to make sure that I never find out. Well recently I found out that he had downloaded tinder, hinge and I think it was pure hookup. What should I do? It bothers me that he downloaded them but it also bothers me that he didn’t cover it up better. I told him if he ever were to cheat on me you either tell me asap or take it to the grave and make sure I never find out. The thing is that don’t have any proof that he actually cheated, I don’t know what he did in those apps. I’m debating about confronting him or just putting it on our past.