World, you're doing fabulously, but don't get carried away with the whole drama of this on here.
That said, whether you divorce or end up back together (and surely after 25 years together, that should never be entirely discounted?), you will come out of this best if you show him - and your daughter - that you absolutely value yourself and will not be taken for a ride.
So, tell him that as he's made his decision, he should go and crack on with his new life, and that absolutely the annex is not appropriate.
Show him that you are making official steps to legalise and end to the marriage, and you are not sitting around moping for him.
Make sure he knows that he will still have financial commitments, but be honest with yourself that he ain't going to be helping you feed the chickens or walk the dog.
Oh, and cancel that credit card for sure, whether his new one has arrived or not. Why on earth would he even want to be spending on her with a card in your name?!