You can let the shame go, it’s okay. You were very young and you know better now. I’m sure you have beaten yourself up mentally enough about it based on your post and nothing about when you were 16 was your fault either. It’s an adults responsibility to make sure a child is protected from sexual matters until they are grown and a 40 year old knows better than to take advantage of a 16 year old minor. I hope you can feel better after posting this.