When I was first making the huge changes to disentangle myself from my marriage to a very unhealthy man, I had to have constant reminders to do things differently.
I actually put sticky notes everywhere - by the phone, my computer, even the front door. Each was a reminder that my ex was toxic for me and any communication was going to be harmful.
One of my stickies had these words:
Oh
Wow
Really
Huh
You Don't Say
How 'Bout that
For those times I had to have a conversation with him about something. Those 6 statements kept me from engaging, and from being sucked in.
Good luck. Change takes time, but there is light and life and happiness and healthy stuff on the other side!