My son will be 5 in Oct. he visits his father every other weekend. His father has brought up that if our son decided to live with him by the time he was 7 or 8, he can. He believes that he is old enough or if that's what he wants to give him that right... Our son even at that age couldn't have a good enough reason to leave me and live with his father. I don't feel like even now his father doesn't do all the right things as a parent and an adult. I feel like his father "babying" him isn't good and my son uses that as a reason why he would want to live with him now or then... I believe if I was proven unfit, that is a reason for a child to live with his father. His father also mentioned that it wouldn't have to be settled in court..? But if it is, what happens? What age?

He is wrong on several counts. A child can't decide. Only a court can. A court ruled on the current custody and only a court can change that. At 7-8 it is unlikely they will even listen to the child.

Also, it would take a lot for a court to remove a child from the current primary custodian. You can tell your ex that if he wants to believe that he can. But if he tries to act on it, he's in for a rude awakening.

Agree at 18 the child can decide, and at 8 years old, I don't know of any court that would even allow a 8 year old to testify.

The facts, actual facts of care is what matters.