I have been there and offered, she obliged, we went but we didn't hold hands, no emotions so it was more of a disaster then anything, she was in a completely different world than we were.
Time to let go of the rope and begin doing things on your own like she is, no need to invite her, but do let her know that you are taking the kids that day, etc. She will probably use that as an opportunity to go out anyhow.
Let her get whatever she is going through out, eventually the fire will burn out. By that time you will have become the best dad, the best person you can be.
