I find that meditating is helpful. It helps me remember that feelings are fleeting and to accept them and let them pass over me. It also helps me discipline my mind so I bring my attention back to what I'm doing here and now instead of ruminating. Think of it like rehab ;-) - repeated exercise to restore your mind to a healthy condition.
I also wonder if you feel like your life is focused on what you want to do. Do you have positive, fulfilling things going on? Goals to accomplish? Basically something that is more important than the anger and bitterness?
M 16 yrs, WH62, P54 3 adult blended kids EA 11/13, BD1 6/14 PA fall 14, BD2 2/15 Piecing 2015, BD3 12/15 Separated 4/16 WH moved OW in 5/16 Divorced 6/15/17