Son wants to live with his dad full time

Me and my husband are getting a divorce and when it came to custody my son automatically said dad. I've always since he was a baby felt like he hated me. He has always been a daddy's boy. When he was a baby he only wanted me to breastfeed and then would scream for his daddy. When he was a toddler I would try to play with him and he would say "No mommy. Daddy only." And as he got older it was dad, dad, dad, dad, dad. He's 16 almost 17 now. And I tried so hard to bond. He came home in tears when he was 15 because his girlfriend broke up with him. I tried to be there. He said he didn't want to talk about it. The second dad walks through the door he's downstairs hugging his dad. My husband was asking what happened and they went in the room to talk about it. Then my husband wouldn't even tell me what they were talking about. Just said "He'll be okay. He just needed someone to talk to." But wouldn't tell me what was said. I've never abused him. Always been there but it feels since he was a baby he has always preferred daddy and now that me and his dad are divorcing he once again picks his dad over me.