I’m sorry op. It sounds really hard 💐 especially coming on top of losing both parents. Confronting the reality of something you are dreading is always horrible.
It sounds like you may have wanted your STBEX to fight a bit harder for your relationship?
You also say that long term you think it’s probably the right thing to do?
One question springs to mind which of course you needn’t answer here. It’s unusual for established couples who have been talking about splitting to remain sleeping in the same bed together. I wonder what has compelled you to do that? Or was it simply a practical decision?
Anyway, it’s understandable to have mixed feelings. Maybe you both need to take a week or so and check back to see how you both feel having made that decision?
If it helps, I heard Esther Perel on the radio the other day, and she says that in her many years as a psychotherapist, she has witnessed all sorts of different outcomes from break ups. In other words, it doesn’t necessarily follow that those who push for the break up thrive the most.
She says she has seen relationships where one part of the couple really wanted to end it and the other didn’t and yet it’s the partner who didn’t want to end it who thrived and the other who really struggled. And vice versa of course but her point is that every couple is different and every individual reacts differently.
I think it’s maybe more helpful to you after the initial shock if you can gain some perspective and accept what is happening (once you have eliminated all remaining doubts on both sides and have checked in again that this is really what you both want as splitting up is never easy when dc are involved.)
As far as your dc go, be careful of predicting the future too much. Yes it’s a fair assumption that your ds with asd will react badly to such enormous change and he may well struggle. Equally, don’t allow your anxiety about this to influence him too much as dc often look to their parents to learn how they should react to something.
If you can work with your STBEX so that you agree to put the dc first in everything, you can really make huge strides between you to ensure that the dc are affected as little as possible. You never know, if you are eventually both happier people after the split, you may both be able to be better parents to them individually than you were as a couple?
Good luck op. I hope it goes as well as these things can.