Children eventually get potty trained so that’s the good news , and around 3 1/2 he will probably be doing it much sooner rather than later so we just have a little bit to go here if he’s a little bit unsure of himself it’s probably that’s more the reason than he just doesn’t want to do it kids will do it when they relax and get comfortable, I think just keep doing what you’re doing just taking him to the toilet after he poops in the wrong place take him back to the toilet and make him sit there for just a  minute or two so that he know he didn’t save anything by not taking the trouble to go there and that little strategy might just put you over the edge and get him toilet trained after all