Interesting point about the third party and worrying about her. Personally, I think that's the sign of a caring, compassionate person, but also probably another indication that you're concerned about your H.'s ability to care for and respect others and, by extension, you too. You're well aware of the hurt he's caused you, but knowingly inflicting that on someone else too can be read as another side of a pattern of not great behaviour.
For dinner tonight, is there a convenient excuse you can give? I'd probably be concerned about how not being there would appear, too, but if it's going to be damaging for you, or if you don't think you can get through it well or might react badly, I'd say skip it - no need to put yourself through that.
M - 34 H - 36 Together 10 years Married 4 years BD - March, 2014