How about, "I'm sure you're asking out of concern for me and the kids, so thank you for that. As you can imagine, I'm not comfortable discussing my marital situation right now. This is D4 day, anyway."
No lie involved. Validate their concern....it's your right to tell them you don't wish to discuss it.
(((((Hugs)))))
Have a great party tomorrow. Keep your chin up, fth..... "When you hold your face up to the light, the shadows fall behind."
