I get the "Eating away part..." That, I'm afraid, I'm quite familiar with.
There's 2 things I pick up here and hopefully you do come back and check.
One is that biologically, I've found in mixed families, there is somewhat of a "double-standard." See, one child is actually his, the BF. The other child, just as significant, in mixed families seem to be more of a, that's YOUR responsibility. It's a tough one.
The part I'm wondering though is, "left-overs" of the ex, meaning if it's over and a cut on the lip, does it really need to involve dragging the ex from wherever to the emergency room.
Secondly, and ESPECIALLLY when it's eating at you, that's your instincs calling. Never hang up on those, lol.
I answer every time and they're usually right, too.
To keep peace both for yourself and the BF, you're right, instinctually, about not attacking. That never works. But instead, softly (and body language will be a biggy here) you may have to practice, because it feels like it's anger in here that's bubbling to the surface for more than just this reason alone.
But I'd start with asking, again, in a soft tone if he/the BF could help you with something you're struggling with.
No matter what, keep the tone humble and for what it is, a question in need of explaining. I'm not talking humble, like keep your head down, just there's nothing wrong w/asking someone who holds the answers to explain something that might help you both sleep better at night.
From my perspective, that's where I'd begin. The EX? From my end, that's an entirely dif. subject you might want to practice keeping for a later time
