I've found since having children that I have become more and more prone to wanting to please others all the time. I used to think that having children made me more altruistic, but it has taken me some time to realize that I have become so accustomed to my role in other people's lives: wife, mother, daughter - instead of my role within my own life. I'm not even sure what I'm sayig makes sense.
The other thing I've noticed is that along with the need to please, was a need to be needed. I'm learning (slowly) to step back a little. I need to know I exist in my own right.