Wendy. I'm glad you talked. I would reverse this though and ask you to both write down what you LIKE about one another, not just what you hate. This is a really good exercise and helps you to focus on your DH's good qualities - and him on yours.
I accept what you say about your Mum not interfering, but I don't think family can ever be neutral in these situations. You've said your sister has very strong views about it all and even if she's keeping a lid on it, it must permeate yours (and his) consciousness.
He sounds like a basically decent man who is wrestling with a terrible dilemma. You've had the most awful lot on your plate in recent years and it could be that it's all proving too much for him at the moment. 40 is a bit of a milestone birthday and lots of people take stock at this time and review their lives.
It is entirely possible to fall in love again, but this requires you to change your view of your partner. At the moment, he sees you in victim mode, which isn't conducive to feeling in love.
I do think a really good counsellor would be better for both of you, than family.
As for a break away, I would suggest that it would be much better for you to do this as a couple, without the children - and certainly no-one from the extended family should be there. In my view, this might be too soon for you both. I'd ask your family to have the children for this whole weekend coming up and spend the time at home with your DH, working through your lists and trying to connect again. You could treat yourselves to a nice meal out or a takeaway in, with alcohol to oil the wheels!
Later on, have those breaks away for just the two of you. They really do help.