She is the first person that I have had this pattern with, where I have not lost my temper and torn strips off them. I didn't think I was going in there to do that today- I really wanted to stay in control, and be assertive, but not lash out and spit out what I think very savagely. I went too far the other way, and dissolved. Somebody hand me a grip.

IG, this^ is what made me think that your usual pattern of ending relationships is to burn them up. So I was thinking to be able to handle a break-up completely differently might be empowering. My fear is that the emotional backlash from going out "in a blaze of glory" may not be the elation and satisfaction you anticipate, but rather a feeling of self-hatred or defeat. Understand, I don't think she can be of help to you anymore; but I want you to walk away feeling strong, not destabilized.

ETA: Glad to see you're going to have some help with this!