I have read your update, and the only thing I can say is
"you are being played like a fiddle"
I am still a member of Binders Army, but your STBXP pulled the 'blinder' today.
He then came out and started unloading it and crying and for the first time ever apologised and asked me to forgive him, we can work it out etc. I was crying too for all the hurt he had caused me. He suggested a separation for a while but I said no, it's over, there is no going back.
You said that today was the first time that STBXP apologised - well he has never said "Sorry" prior to today has he? But he did today and has actually offered to move out tomorrow.
Phew! he finally got it!
Now read this sentence I think I've really got a chance of us staying here I assume you mean you and DS, but you might mean you, DS and DP.
Binders, stop and think. Do you want to find a way to fix it? If you do, nobody on this thread will think any less of you. You have had great advice on your threads, but do YOU need some time to think? The Binders Army don't have to live with the consequences of your decision, nor does Ms Rottweiller.
If, after today, you are still clear that you want to finish the relationship, then your Binders Army is behind you.
Still saying prayers and sending positive thoughts 