boyfriend advice needed

So me and my boy have recently been on the outs and we broke up for a bit. we are back together now but while we were broken up he snapchatted other girls and I did the same with other guys, but the thing is I sent nudes to some of them and I feel really bad. I'm having this abundance of guilt and I havent told him this yet but he hasnt told me about anything he did either. I found out from the girls he sent ab pictures to. should I tell him or should I just wait until the subject comes up? we're both in the wrong, I just feel horrible