Cheating? 🤔

I noticed scratches on my husbands back today after he got home. I’ve never had to worry about something like that before, so I just full on asked him, why does he have scratches. He said “I don’t have scratches on my back, if I do it’s from you.” Then there was a long silence, and he said “I hope you’re not trying to accuse me of something just to cover up for yourself.” I kind of got aggravated after that and went to lay in bed. So then he comes upstairs and lays down for bed sometime later. And he just randomly says “you know, I don’t accuse you of cheating at all.” And he just goes to sleep. What would you gather from this?? They look like scratches on both sides of his back from sex. And I was popping pimples on his back this morning and they weren’t there. We haven’t had sex together in a few days either. Do I try to find more evidence on my own to figure out what’s going on??? I’ve literally trusted him our whole relationship so far