RD, I just had another thought. You're clearly a lovely and quite a nurturing guy. Do you think in your sitch you have become something of a father (or caring older brother) figure with your W. And that your approach may be enabling her to stay in child/teenage mode - because she doesn't really have to stand on her own two feet?
Some things you've said - getting her tyres done for her. Offering her £50 to keep her going - these would be just the kinds of things my Dad would have done when I was single. What if you took the view that - hey, you fired me as your H - these things are yours to own now. Not in a nasty way of course. More in a 'hey, I'm sorry to hear that. Hope you manage to get things sorted - gotta dash..." kind of way.
Why not just try ceasing any form of support right now - no listening ear to her woes, no practical 'fixing' support and no additional financial support. No mediating when she fluffs things up with the kids. Just giving the impression that, hey, I can't offer all of this to you any more - you'll have to find that somewhere else/sort it out for yourself.
My other thought is - what if you were to make some plans for a Wednesday night. And instead of your W coming over for family time, she comes over to 'watch' the family while you go out for the evening. Maybe not every week - but some weeks. What if you were to positively plan a drink out with a friend or similar that night and say to W. Just checking you'll be coming over as I'll be out that night.
I think these two simple changes do the following things. End any potential father/child dynamic. Force W to deal with her own stuff. Help you do something new for you. Help end this feeling of - hey, I just helped you and you're texting me from outside OM's house. Start to give W the message that RD wont always be there for me like my reliable Dad or older brother, so I'd better do some thinking here. He's become a bit more of an unpredictable guy...I think all of this would shake things up a little. Not being too extreme about it (bearing in mind your W's vulnerability right now) but just giving things a little mix.
Maybe all of this is a bridge to far, and forgive me if I'm crossing a line here. Maybe see what others think too.....
(((RD)))
T 13 M 7 Me 48 H 46 SS 15 BD 7.14 PA D final 5.16 (H filed)
We receive & we lose, and must try to achieve gratitude & embrace with whole hearts whatever of life that remains after the losses - Dubus