So my son potty trained at a little over 3 years old. I took a friend's advice (which came from her pedi) and just LET GO of everything for a few days.
I basically treated an accident like it was nothing.
He would pee and I would say let's go change your underwear - you peed in them.
Monotone voice - got the underwear - put them in the laundry. As I put on new ones I would say - "Ok - next time you have to pee - tell momma and I will help you go potty. Now go play (or watch tv or whatever he was doing) and tell momma when you have to potty - ok?"
WAIT FOR HIS VERBAL RESPONSE TO THAT... ask really nice/monotone until he says ok.
Don't sound bored, just say it like you were saying "I love you, go play."
Basically - try not to hype it up or down in anyway. I went through exactly 3 days of this and ALL OF A SUDDEN he just went by himself!
I got him a stool to get up on the potty easier and a little potty insert for the potty. He wet himself for about a day and a half and then needed my help going to the potty for another couple days but after that - smooooooooooooooth sailing.
At night I just told him, "Come here - it's time to put on your night time underwear." I never called his pullup a diaper. I just said he has to wear special underwear at night like he wears special pajamas (we got him some special superman pjs with a cape).
After about 4 months (recently) he said he wasn't a baby and he wanted to wear real underwear at night. I told him when he woke up and his special night time underwear were dry we would let him wear real underwear.
We bought a $4 vinyl (plastic) cover for his mattress at Wal-Mart and let him sleep in undies. We have had a couple of accidents, but that only happened when he drank too much after 7 or so.
Anyways - basically just go outside - scream - and then let go of everyone and everything that is telling you otherwise and just think:
He will probably live to be about 80. So this time right now is such a tiny part of the grand scheme of things. He will pee and poo in the potty before he is 5 I am sure - and it may take some time - but when you just forget about forcing him to do something, it will work.
Just treat it like it is just something else he does. Like eating or playing. The moment he gets any attention he will keep aiming for that. When he DOES go - be REALLY happy about it and talk up how big a boy he is and how you are SOOOOOOOOO happy.
When he has an accident, really try to show no emotion whatsoever. If you try the every 15 min thing - don't force him.
I tried that and it set me back weeks. I was literally trying to potty train my son for a year. (We had a baby in between all that).
Anyway - make sure hubby is on the SAME PAGE. Just try it for a week - I promise you will not regret it. I had a few people (family - friends) making fun of me or saying I was babying my son using this method.
Well - I potty trained my kid in about a week and had lots of laundry. My son only needs help with wiping after he poos, and other than that is self sufficient.
Their kids are still having accidents, and they are pulling their hair out and living with pee and pee everywhere.
I was the same way - but once I literally just let go of all thee stress and frustration and dealt with the nasty undies - that few days just went by so fast. It will be a nasty time before he gets the hang of it - but in the long run, you will never remember this time like you think you will.
Any other questions - private message me. Hope this helps!!!
(sorry for the novel, haha)