You're essentially asking him to choose between you and his son. He wants to be involved with his son, and as he doesn't have full custody moving away will mean he will see his son significantly less.

It's not so fun that he's basically strung you along. But really.... You asked him to move after you'd only been together for a year. Then again after two years.

You've been together for three years now. So you ask him once a year?

What's more important to you - him or moving? That's what your decision has to be. It's not really fair to ask someone to leave their children behind just to follow you.

He has decided that his first priority is his son - which is great! He obviously does love you since he has wanted to consider it, but his son is his first. Which is normal for a lot of parents.