My son is like 70% potty trained

OK so he uses the bathroom when he wants but he’s been recently pooping in the toilet so that’s good so today I put him on some boxers and he didn’t pee on himself all day and he used the bathroom but when it’s time for him to go poop, he always wants me to follow, like how do I fix that? I don’t want him to always need me to go to the bathroom with him. I don’t mind doing it with him at his age because he’s three but I don’t want him to be like five and always want me to be in a bathroom with him when he goes, so how do I break that