You do seem pretty happy in your life and it will get better, but in the ways that you want it to.
The reasoning of not wanting to be Divorced because you want to know you tried everything and stood for your M is good. Having that kind of peace i think is probably a good thing.
Definitely until you feel ready to accept it then i dont think it makes sense to file, particularly under the UK system, but thats just my personal opinion.
as for the 'so he cant marry' aspect thats just something to be cautious of as it drifts into the territory of trying to control him.
Again its only my own opinion but whether he wants to marry someone else I'm not sure matters in the scheme of things, because the marvellous Toots deserves someone who wants to be with you and wants to share in your life. If its short of that then it doesnt matter whether its a just short or a country mile short - You, Toots, deserve better.
Both mid 30s, 2 young kids BD 7sep14 XW moved on long ago, now living with OM1 D paperwork in progress