I'm just musing here. I was cheated on by a partner a long time ago - I was in my mid-twenties and we'd been dating 4+years and planning to get married etc. Then he asked for a "break" while he figured stuff out, and clearly already had started seeing the OW. Came back to me after the break, but kept messaging her. I finally found out and kicked him out.
I'm not still angry about any of it. I think he did me a massive favour because I was young, I could bounce back, I built up some self esteem and don't take BS from people, I had other relationships and eventually met my DH.
But back then I knew that he was the one who cheated / he was the one who treated me terribly.. but I still felt some amount of anger at the woman. I've more than once found someone who is in a committed relationship hitting on me (far away from their partner, usual BS after drinks about how partner doesn't understand them etc) and I've always just left and stayed away. Even though I was single, I didn't want to do that to another woman.
Others who've been cheated on, do you genuinely feel the OW is not at fault at all? Of course the person in the relationship is the person primarily at fault. But do you not feel anger and betrayal from also the friend or acquaintance or person who ate your food and drank your wine and then kissed your boyfriend? Or even didn't know you at all but knew you existed and didn't care?