Hi A.,
We are just starting the potty with my daughter (22 months) but we had some of the same issues with my son. He started early, (16 months) because he wanted to be like the big kids at daycare, but lost enthusiasm along the way. As long as I stayed on him, he was completely potty trained, but would never initiate going on his own. He would be so busy playing that he wouldn't stop on his own to go. (This was so annoying, since I knew he was perfectly capable) After the birth of our daughter (he was 29 months) he completely regressed. The pediatrician told us to completely back off for 3-6 months, (she said 6 is probably better) so we did since his entire world had just been disrupted. I would still occassionally ask if he needed to use the potty, but I never pushed it. We continued to use pull-ups/diapers for this time period. At this same time we were trying to find something that would be really motivating to him. (stickers and rewards/chocolate simply were not working for him). We finally discovered that he really wanted to go to preschool. We eventually told him, he didn't have to use the potty, but he couldn't go to school until he did, since no diapers were allowed at school. (We were not lying either, the preschool we planned on using didn't allow pull-ups/diapers). We got two mason jars. One he decorated with stickers etc, the other we filled with pebbles and left plain. Everytime he peed, he put one pebble in the school jar, every time he pooped, 3 pebbles. Anytime he had an accident (pee or poop), 1 pebble went back into the original jar. We didn't make a big deal about it. We would just say, oh, looks like you're not dry, you didn't make it this time, try harder next time in a regular voice. Then instruct him to remove a pebble. He knew that he had to fill up the school jar with all his pebbles if he wanted to go to school. My daughter was about 6 months when my son came to me (on his own) and said he was ready to use the potty. He went in and went on his own. I asked him if he wanted to wear underwear, he said yes, and we have been wearing underwear ever since (including night and nap). Not to say he hasn't had a couple of accidents, but not very many. Most of the time when he has an accident, it is when playing outside at a friend's house, because he holds it too long, then can't get inside to the bathroom quick enough. We just had to wait for him to want to do it. For us, school was all the motivation he needed. We quickly filled up that jar of pebbles and enrolled him in school. My suggestion for you is to back off, he may just be feeling too much pressure right now. Give it a break and then try to reintroduce it but let him take the lead. We used to tell my son to listen to your body as a reminder to pay attention to the urge to go so we weren't constantly asking him, do you need to go to the bathroom? I swear, when we asked him if he had to go, he just tuned us out and automatically answered no. Possibly find something that would be motivating for your son, so he has a goal to work towards. Lots of patience and love, my daughter is already testing my patience on this. I think I am going to wait a couple of months for it to warm up, then let her run around naked outside for a couple of days until she gets the hang of it.