My son wants to live with his dad.

So my son has been wanting to live with his dad for almost two years now. And I'm pretty sure we came to an agreement that he will go live with him. He is going for his normal visit he usually does for the month of July then coming back here for August. Then he will be moving there and going to school there. He is about to be 11 years old. I feel very sad but also I know he needs to be with his dad and think it will be good for him. My husband has been in his life since he was 1 year old. And it is hard for him as well he feels very bad. I don't want anyone to think I am a bad mom for trying to do what I think is good for my son. Has anyone else went through this?