Finding out my husband had sex with my best friend

Me and my husband have been together for 4 years. I've been friends with my bestie for 14 years. I found out that they had slept together MULTIPLE times before we got together. My husband does not remember her because it was from back when he was addicted to drugs and she was a red head back then. She was blonde when I started dating my husband. She never told me. She said it's because it was 8 years ago and she could tell I really liked him and didn't want to ruin it for me. So now I have to live with the fact that my husband has seen my best friends pussy. Fucked my best friends pussy and done it on multiple occasions.

@marike I'm pretty confident he doesn't remember her. He's not a great liar and he doesn't remember a lot from the time he was struggling with addiction. So with his addiction and the fact that he most likely just remembers sleeping around with a red head along with some others girl I think he truly doesn't remember her

@Diane as I said my husband doesn't remember a majority of that time in his life. Even if he remembered he saw her somewhere that's not the same as remembering he had sex with her. He doesn't even remember the assault that happened to him. Someone has to tell him it happened. He also doesn't remember when he ended up comatose from his addiction. So I don't think he's lying when he says he doesn't remember her because he is missing like 10 years of his memory.