Breaking the pattern

My Mom is a narcissist. I have done a lot of therapy around that relationship so I know how to mange it. However there is a pattern in my life where an older women appear and I am blind to what is happening until I am sucked into a pattern that is just like with my Mom. The older woman will make demands and I feel like I have to say yes. I feel like this because it feels dangerous to say no. Even though they are friends not a parent.
I end one friendship because its not healthy for me and then another person shows up. It would be comical if it wasn’t so painful for me.
Yesterday I told the current friend that I couldn’t do something she had asked me to do, this was very hard for me, then straight away she makes another demand…something that I have already told her I can’t do at least twice before.

I am so tired of the pattern, and want to put a stop to it but it feels really really hard.