I am legally S and will move it to D in the next few months.
I did this on the advice of my lawyer (I am in the UK btw).
Here the S agreement deals with split of marital assets, financial settlement (child support and spousal support if applicable) and arrangements for any children. It is legally binding on the financial matters but not on the issues relating to the kids.
So why did I do this? First, WXW was all over the map and I wanted a clear financial settlement so that I could keep the house. It took ages but we more or less negotiated it between us and I got a L to write it up. Going straight to D would, I believe, have escalated her emotional response and as a result made the job of getting a good settlement all the harder. Legal S seemed to her less confrontational and final so she could cope with it all better. That was my judgement relating to my own situation. I think I was right. I should add that I did this not to save WXW any grief, but to save ME grief and allow me to get the settlement I wanted and needed. I did.
Secondly, the kids. The LAST thing I wanted was a fight over access to the kids and again moving to D could have really escalated this. It took me a long time to negotiate the access I have to the kids and its all documented in the agreement. Now this is not legally binding, but the advice of my L was get it in the agreement and operate the childcare on that basis - when it comes to D, judges here and very reluctant to change the status quo. At the point when this all blew up the status quo was that WXW did most of the childcare. I have created a new status quo, documented it, have been operating it for two years and can demonstrate that it works. This would now significantly weaken any case WXW might want to bring for increased access to the kids.
So - it has worked for me. Now I want to finalise things via D and WXW has said that she has no issues with our arrangements as they stand, so I am hoping that it will go through smoothly. The legal S agreement is a HUGE step towards the final D.