My DS ages 2 and 4, have coped well with my separation. I actually felt they would cope better being younger. They generally tell me at some point each week that they miss their Dad, want to see their Dad, that they don't like me and want their Dad etc... I try not to take it personally, but it does make me sad.
I'm sure when they are older, they may request to go live with him, I can only hope that they will want to come back home to me once they realise the grass is not actually grener on the other side.