I just worry that simply insisting on this trip without the rest of the work will not be the best way for him to gain his own self respect and get his marriage back on track.
Agreed, 100%.
Neither will cancelling the trip and doing none of the work.
IMHO, the key is to try very hard to increase your mutual understanding of what this is really about, and what your going or not going would mean. And, if you still feel like going would be best -- that, despite her expressed concerns and issues, you still feel its best you should go -- then go. Don't go against your judgement because of her whims or irrationality or difference of opinion. My 2-cents.
