S.W.
I am going through the same thing with my son (same age). My husband and I set him on the potty and say, "Let us know when you're all done." Then we leave (stay within ear shot) and let him do his thing. This frees us up from hanging out in the bathroom all the time and it gives him some independence. He also doesn't want to be in there as long if he's by himself. It's a win win for us all. Then we ask him if he went potty and when he says yes, we celebrate. Good luck.