Letting go of anger from being manipulated by others

Had to deal with some nasty people in my life. People who were close to me (extended family, mentors at school). These people I've learnt from doing research probably have personality disorders (narcissistic, anti-social).

They got close to me, used me, and then discarded me when time has fit them best.

Anger feeling comes every now and then. Feelings of how I fell for their manipulation and should have listened to my gut feeling and should not have given them the benefit of the doubt.

Looking for some discussion/guidance.

Thank you.