Should I tell him I cheated?

So I did a bad thing, obviously. I cheated on my boyfriend of 9 months with this stupid fuck boy. I’m only in high school mind you. I sent pictures to the F boy (if you know what I mean) and flirted with him, hard. It definitely counted as cheating. I don’t know what was going through my head, it’s terrible what I did and I don’t think I’ll ever forgive myself for what I did. My boyfriend was away so I was lonely and I justified it by saying I was making things even cause he did do some shitty things in the past to me. But I know now that I was a stupid fool for that. I’ve already cut everything off with the F boy, but the guilt rest on me heavy. I made a mistake. Should I tell my boyfriend what I did? I know that it’s the right thing to do but I know for sure he would break up with me and it would crush him. He gets anxiety about this kind of thing very easily, all the time, so telling him could quite literally break him. I’m not sure what to do.. should I tell him and then we’re over or keep it to myself and try to fix things without him knowing what I did? I love him and I don’t want to lose him...