I let my son live with his dad

Hey so my son is 4 and has been living with his dad for a few months now. His father and I are still married but aren’t together anymore and don’t plan on getting back together. Last night he asked if our son could live there with him and I get every holiday and school break. I said yes because right now I am not quite yet back on my feet. I don’t want him to be here in my hometown and turn out like the boys here and feel stuck, with his dad he is in a great private school and is super happy. Did I do the right thing or am I a horrible mother for letting my son go?