I am not in my best state of mind latley but I am going to try to answer. I know I have an answer, I am just not sure how well I can articulate lately. So let me see if my brain will cooperate.
Basically we do this as second nature and it is hard for us to realize when we are doing it, but we learn to become attuned to it by noticing the feelings we have when doing it. For instance when we are trying to perform there is often a performance anxiety that comes with that or maybe some other feeling that we push aside like "if I don't do this then(enter negative feeling/belief here), but it's there and you have to allow yourslef to notice that and that is how you will be able to tell the difference. You learn when it feels good for you to do for others and when it doesn't. I think it will become less and less about your fear of rejection and abandonment as you work through those seperately. But we all have little issues and some of these will not disappear completely. That is when our awareness allows us to manage them.
I hope this makes more sense than what it seems to. But to be honest it is a little confusing and it is not as simplistic as I may have made it sound. Like you just become aware. It takes effort to notice and it is not always easy and it gets better with practice. Its about being attuned to your feelings and body and listening to what it tells you. Your T can help you do that.
Anyway, I better stop now before I have everybody saying "huh??"
Hopefully someone else can come and explain better. I'm going back into my little corner again.
JM