Okay here goes... We successfully potty trained my DS when he was 2.6. It took about a week or two for him to be fully reliable and he pretty much night trained himself (his pull ups are almost always dry every morning). He is now 3.1 and since about 2 months ago he doesn't seem to get to the potty/toilet before wetting his pants. It's always a small damp patch as opposed to a puddle but he only ever does this when he is at home with me. I work 3 days a week so for the rest of the week I'm changing his pants and sometimes trousers if it goes through at least 2-3 times a day. He's completely dry at nursery, even taking himself off to the toilet without being asked and mostly when I'm out and about at friends houses etc. he remains dry.
I have tried everything (to my knowledge!). Asking him politely if he needs to go, reminding him, encouraging him by letting him know it's a good idea and saying it isn't comfortable to walk around in wet pants. He generally goes once I've mentioned it but a lot of time by then it's too late... but a lot of the time when I suggest it he fiercely shouts no only to go a minute later (his terms not mine!) - but still with wet pants.
It feels like it's a case of him being too distracted or engrossed in playing to go in time but I don't see why that should be the case just at home when we are playing together. He can manage most of the other time.
I've considered the possibility UTIs but as he spends part of the week dry and part wet I'm not sure it can be this and I don't think I want to put him through getting a sterile sample for testing as it sounds very tricky from what I've read.
I think it's mostly a behavioural thing but I am all out of ideas. He knows what to do, he has a potty right where he plays or a toilet in easy reach (he chooses which vessel!).
Any ideas? I'm struggling not to go insane over this!