I'm in the process of owning up to the core problem with my training:
fear and lack of physical conditioning..... And BTW, "just choose to" is a non-answer, right up there with 'don't get hit' and 'just throw him'. If your answer is 'you need to figure out what works for you,' tell me what worked for you. I apologize for the frustration, but I'm finding it difficult to 'just' decide, and it is hard to look for advice and find platitudes.
If you are having a hard time doing one thing -- do the opposite. Let somebody hit you. Really, move aggrsssively into the strike, not to throw -- just to get hit. Get hit a lot. Then you will know where the break point between being hit and not being hit really is. Then -- live there. The rest will take care of itself.
Similarly, if you are having a hard time throwing don't throw him, just commit to be standing where he wants to stand -- always, every time. If he wants to be in a place to do something -- meet him arriving there. Get good at this, and throwing is an afterthought. If he is in your way, realize he is not an obstacle -- he is just standing in your spot, so walk though him to get to it. The when you have this down, realize that everything done from a further distance is still moving him out of your spot, just from farther away.