It probably will be more effective to your cause than actually going. w will most likely reflect more on you not wanting to go, than all interactions throughout the meal.

Regardless of if/how W reflects on that, you do what is best for you. IMO you choose rightly.

Best wishes

R 25 years
M 14 years
S11 & S13
Working on it alone since Oct 2014
M in trouble a lot earlier (~2 years)
Feb 2016. 1st R chat in a yr.
Next R chat Aug'17
Still together