AITAH for telling my wife the truth about why her cousin stabbed me?

On a burner account. I'll write what happened leading up to me getting stabbed.

My wife 30 has a cousin she is very close with. They have bond closer then her actual siblings. I was part of his group of friends when I meet her. I showed interest in her but her cousin told me to back off because to be fair I wasnt in the best place at that time. Substance abuse ect. Still didn't stop me from secretly trying to talk to her and get to know her though. She was nice and I thought I'll try my chance but I left it to late. She started dating her ex and moved away.

I thought that was it until she moved back with her sons. She was pretty heart broken. Her cousin had a party at his house couple months later. I knew it was dumb idea but I was asking her cousin about her and asked for her number but he told me to go back to the party and I argued and so he started shoving me back towards the party and I took a swing and I ended up getting stabbed. Got a scar for it.

Scared me and realized I could have died and started making better life choices and cleaned myself up. It was chance that I meet her at the mall and we got talking. Eventually led to us getting married. Then couple of days she finally got curious about the scar and I didn't want to tell her because she still close with her cousin. But she pushed and I told her. She went pale and said he wouldnt do that. I said it doesnt matter it in the past now and we both grown up alot since then. But she went back inside and now I regret telling her about it and hurting her. She hasnt been talking much. AITAH for telling her?