I'm not GEL, but I hope you don't mind if I jump in. First, I think maybe the 'attack' thing is something that is going to come up no matter what - think how you'd feel if the tables were turned. If you can stay calm, and make the setting comfortable, be on the same level, not 'looking down' on W, it should help. Don't start with what I did last night, start small (H and I ahve had several such talks previous to last nights).
It helped last night that I could start by picking up on an earlier convo, and asked him to clarify something he said. I think this made H a little more comfortable - I was showing an interest in something he said. Don't 'expect' answers, don't even 'expect' any kind of result - W may be too overwhelmed to even comment. Give her a chance to, though, if she wants, and listen carefully, validate what she says.
I've found that going over what I want to say beforehand keeps me calm, and helps me to figure out how to say things with minimum 'attack' content.
