If you are not comfortable with a separation agreement then do not participate. There doesn't appear to be a legal reason for the document so it seems mostly ceremonial.
Hope, can I ask a sincere question? Why would a S agreement not be helpful to Jefe? I understood your worst-case decision-making matrix, and, having been in a close relationship with an alcoholic myself, understand it quite well. But, why must Jefe fly by the seat of his pants? Why can't decisions be made that apply to longer than today? For instance, he and W decide that W picks up the girls at noon every Sunday and drops them off at school every Monday? How is deciding that weekly more advantageous than deciding it applies to the next six weeks?
There is no legal S in my state. H and I have a (non-legal) S agreement that spells out the length of the S, whether we can date, how finances are handled, and a parenting schedule, among other things. It's not ceremonial, it's practical.
I admire the advice you give on the boards, and look forward to your thoughts on this.
