C.,
I have 3 children, the youngest my only son. When it came to potty training the girls were a breeze. Praise was plenty. My son would hide behind the couch, do his business, and then ask to be changed, because he did not like sitting in it. I tried EVERYTHING. Stickers, M&M's, begging, praying. (Diapers for 2 takes a chunk out of the budget). Anyway, my son loved cars and trucks. I bought $9 worth of matchbox cars @ 88 cents a piece. A great investment.
Every time he would successfully make a deposit, he could open the car of his choice. I knew he had mastered complete control when he would make a partial deposit,choose a car then go back 5 minutes after playing with the car and finish the job, then look for another matchbox!
Once we moved to big boy pants, i would reward him with other things to motivate him and keep him focused.
Don't get too stressed. He will come around. But also don't enable him to fail too easily. Once you 2 are ready to work on Potty training, GO FOR IT! Dump the diapers. Watch what time he has his last drink at night so he can have dry mornings. I still make my 9 year old go to the bathroom before he goes to bed no matter how tired he his. It is better than seeing him so disappointed in himself first thing in the morning, and then having to deal with the clean up!
GOOD LUCK. Hope this helps.