Am I the asshole for poisoning my husband

Me 38 female with my 40 year old husband met when I was 21. I met my husband on a business party which my best friend 30 female invited me to. When I met my husband we immediately bonded. After the party we became very good friends and he told me that he likes my best friend. I supported him, but my best friend had a boyfriend who she loved. Me and my husband tried to get rid of her boyfriend, but unfortunately he proposed. At her wedding my husband decided that it is over. After her wedding me and my husband became closer and then finally fell in love. He proposed to me 6 years after dating. We had a beautiful wedding and we had 2 twins. But lately I have felt that my husband didn't love like he used to. I was crushed and tried to find out why he was distant. Then I found out that he was cheating on me with my best friend. I was so angry and sad. Yesterday it was supposed to be our 10 year anniversary and I told him I had something special planned for us. I recreated our wedding cake, but with strawberries in it, because he is allergic to them. Then I confronted him and asked me why. He said that he had always love my best friend and that I will always be the second option. He even said that I got old and put on some weight and my best friend was 8 years younger and looked like a model. I tried to give him a second chance but that was it. I told him to at least try the cake and he had to go to the hospital and I filed for divorce. So am I the asshole for poisoning my husband?