Almost 4 months since STBXH owned up having OW (not his first, 2nd chance was given 3 years ago and obviously squandered) and while I am sad and angry on the kids' behalf, I know that in the long run I will be fine, but OMG the hurt: he walks OW's dog - never walked ours, they are currently away on the trip of a lifetime - I am the traveller in the family, much more interested in places and people rather than things, he tells me less than he tells random passers by - I literally don't know where he is in the world just now, just that there is 'rain forest', but he has told the postie.
I am seriously struggling with coming to terms about quite how much he clearly is not the man I thought he was, not the man I thought I had married 20 years ago, not the man I lived through considerable hardship and heartbreak with.
How off must my judgement be?? I loved him a lot and as father of our children in some odd way still do, but what was I thinking hitching my life to his?? His self-absorption knows no end, it is literally as if he had taken leave of his senses.
He has ditched us in order to be able to lead the kind of life I would love to live. With somebody else 
He needs me to mind the children so he can swan off - I am staggered by his behaviour and cannot stop thinking about what an idiot I was.
Does it get better? Sigh.