That's funny- I've always known about OW since BD and I've always called her "your girlfriend" to H as well because I was actually trying to be conciliatory and I thought it was the least perjorative.
Watch out for the defensiveness - it can easily turn to anger and more jerkiness. In light of recent revelations - I asked if H really meant it when he said he was going to help us keep the house and he immediately got defensive (and hostile). How dare I question his integrity? I realized its probably a better tactic to continually thank him for helping (despite the fact that its the decent thing to do, etc).
They feel guilty and then that turns to defensiveness and then to hostility.
I'm concerned as well. For starters H has always placed a huge amount of stock on advice from friends and who knows who is advising him right now? He's already said that the people he has talked to said it was "unavoidable" to use a lawyer- My guess would be some bitter divorcees. So, for the sake of harmony and the kids, I'm just going to have to continually resign myself to being the constant bigger person. Truthfully he could bankrupt us both - so I'll just keep emphasizing the lower cost option.
Thinking of you Ahoy - I hate this for both of us!