Potty training question

My son is 3 years old and he has been trained for pee pee for about 3-4 months now. He doing great with pee pee so far. When it comes to poop. He would hold it and beg us to put him in diaper. If I take him to potty at the time he would not go but hold it in. Sometimes I will go 2 days without putting him in diaper and he wouldn’t go all 2 days. I am not sure how to help him I tried putting him in diaper making g him sit on the pottt etc. nothing works. I am super frustrated and please help me