Hello, so I have been lurking on this topic for a few weeks, I threw H out in September after finding out about his affair, have two DC, aged 2 and 4, have had a pretty horrible time of it but chugging along, as you do. He has predictably followed the usual well-worn path of decreasing contact/maintenance, OW and her family becoming his priority over the DC, like I say, pretty predictable.
I have maintained a good relationship with his mum, we always got on well anyway and she and the DC adore each other. We have never really discussed H and his behaviour - he is 'living' at hers, although in reality spends the majority of his time at OW's house with her and her DD and her mum cosy!.
I respect the fact she is in a horrible situation, and I have no argument with her. However, H informed me a few weeks ago that his mum had met OW, which I was pretty upset about as I felt she had betrayed me a little bit, silly I know but still. I have found it difficult to be too friendly with her since then. So tonight I popped over to drop the DC's stuff off, he only see's them at his mums because otherwise he'd have to feed/bath/dress/look after them himself and took the opportunity to have a quiet word...
Turns out she has BANNED her from the house and only 'met' her because H had sneaked her in thinking his mum was at work, she came home early and they were busted! MIL was most pissed off and told me that OW is absolutely not welcome in her home :)
I feel much happier :) The little victories are sometimes the most significant ones. I had a little cry and said thank you.
This doesn't really need a response btw, I just wanted to write it down :)