I saw something on my SO’s phone because I snooped. I’ve snooped before and found something I didn’t like. He said I misunderstood and I believed him, and he didn’t get mad. 
I did it again, and found more that I didn’t like. I don’t want to ask again because I know it will start the same conversation and won’t go anywhere. 

But I can’t stop thinking about it. It’s obsessive and he’s noticed me acting different. What should I do? I can provide more info if you want.