I find that when I'm more involved with things that interest me and have friends that I can meet up with, I'm less prone to emeshment with whatever emotions that are engulfing my own so. Not that I'm not sensitive/aware/in tune with what he has going on for himself, at the same time, my day isn't made or broken over it. I spent much time in my own therapy work and self help learning to untangle myself from my own overbearing childhood into adulthood and untangling myself from quite the emeshed and abusive marriage. The word boundaries is elusive on the surface because it's not really about rules. It involves a level of detaching without being closed off. It's about learning to be unaffected by the emotions of others.
I actually did my own anger self help work. Because being a people pleaser was causing enormous inner turmoil for me. Was creating through lack of "boundaries" enormous resentment because it was becoming a situation where everything was done to appease everyone else and my own desires were being ignored, brushed off, unimportant. The timing, looking back, was good because I could then grow while my kids were/are young. It is paying off with my career, as well.