hello Tonyacorn
a warm welcome to TP
what a tribute to your wife and your m-I-l that you are happy to visit so often
and it's not easy keeping going when the visits can sometimes feel so negative and demanding
the compassionate communication thread Cat27 has linked to was a real help to me in getting my own head around how things might be for dad - I've become very good at making neutral noises and staying calm and pleasant with a smile, even when I want to just tell him to be quiet
- definitely no point in arguing or explaining; distract (dad loves chocolate biscuits and doesn't talk with his mouth full) and if necessary even walk away fro a while and go back with a cheery bit of nonsense to talk about
if she says you haven't visited, go with it, apologise and say work has been demanding (or whatever excuse will appease her) and you're so glad you've been able to get away to have a chat with someone pleasant ... butter her up
about the other woman - make a little light of it; might you risk a 'how could anyone take the place of your daughter; I had the best, not worth even thinking of looking' and then immediately change the subject to something your mil will engage with or just talk at her for a few minutes - would it be possible to look at old photos with her to show much you all enjoyed 'the old days'?
best wishes