Am I The Asshole for exposing my husband's affair with his much younger childhood friend

My (34F) husband (36M) and I have been married for 12 years. We have two kids together, ages 10 and 8. Everything seemed perfect until I discovered that my husband has been having an affair with his childhood best friend, "Emily" (22F).

Emily is practically family; our families have been close for decades, and she was often at our house growing up. When she was a kid, my husband used to babysit her. I always thought of her as a little sister, so you can imagine my shock when I found out they were involved.

The affair started when Emily turned 18, but I found out through messages on my husband's phone that he had been grooming her for years. He bought her gifts, took her on "special" outings, and made inappropriate comments that she didn't understand at the time. Now that she's an adult, their relationship has turned physical.

I was horrified and confronted my husband. He tried to downplay it, saying they were just old friends who got too close. But the messages I found were explicit and clear.

I decided to tell my family and his family. My parents and siblings were outraged and supported my decision to leave him. However, his family is divided. Some of them think I'm overreacting and that it's just a "midlife crisis." Others are appalled and think he's a predator.

Even our friends are split. Some believe I should forgive him for the sake of our children, while others agree that what he did is unforgivable.

I've moved out with the kids, and we're staying with my parents. Now I'm being accused of overreacting and breaking up our family over something that "isn't that serious."

So, AITAH for exposing my husband's affair with his much younger childhood friend?

I want to clarify something real quick. My husband and Emily’s relationship is more of a Brother-Sister bond but I didn’t know any other word to describe it so I used “Childhood Friend”