S.O.
My 3 1/2 year old is FINALLy getting it (boy) and he started using the potty of his own volition at 19 months. so! I understand being frustrated with the process. It took a variety of 'carrots' to get "O" interested again in the potty after his brother was born (1 1/2) but to get him to go consistently required a few things: a scaled back schedule for a while (more time at home), a true change of attitude from mom and dad (we were both trying very hard not to exude any sort of urgency, but can not hide feelings from this kid very well. WE had to actually change. NOT feel frustrated and urgent because he just wasn't buying the act! THis is the hardest thing to do), a little time in the nude. Ok, we are not crazy bohemians here. we just found out that letting him hang out in the buff helped him to connect with when he had to go.
The big thing too was realizing that we could tell him 'It's time to go sit on the potty'. WE were thinking too that forcing was counter productive, but found with our boy that he needed to have us help him establish the routine. WE still give him little treats (his gummy vitamins or extra time up at night) for going #2 (the big hurdle for him) but now he seems very happy with himself when he goes #1 on the potty and doesn't ask, except occasionally, for any kind of reward.
A couple of things you can invest in that might help. THe little potty. SOme kids hate this. My son will NoT go #2 on the big potty, even with a stool to prop up his feet. Potty books from the library- once upon a potty (our fave), no more diapers for ducky, you can go potty too!
I know this is a lot of info- I hope it helps. good luck. hang in there!