Apologies for the long rant.
The situation is that my exH is relatively comfortable (around £5-6K / month de facto net income, paid off house, semi retired in 50s). However, there's nothing on surface to attach official maintenance to (both through CMS or family court). All gifts from family, unexpected windfalls, relatives and girlfirends suddenly becoming preferential shareholders in his ltd company and drawing dividends etc. I can provide details but just trust me that I tried every avenue possible (where proportional to do so). It is a matter of principle for him to not pay anything, he has admitted it on a couple of occassions (with some perverted pride).
There are two young children, and we are divorced from before the youngest was born (he left for someone else). I managed to ambush and catch him only once, when he had to pay maintenance for a few months and then - oopsie daisie, a sudden "change of circumstances" reported again. He sees the children infrequently, lives his own life - hobbies, travels the world, returned to education etc.
I am lucky in that I can provide for the children reasonably well myself, both basics and some treats too. With 80 hour working weeks and no paid holidays, but it is still a very privileged position to be in. I do sometimes worry as I am nearly 40 and have almost nothing to show for a pension, and the only mortgage that was affordable to me stretches into the age where I will make the final payment on the house and probably move into a care home soon after. No savings to worth mentioning either. But overall it is not too bad at the moment.
Realistically, it has been going on for more than six years now, and he treats it as some sort of sport - he spent more on lawyers now than the wildest estimate of total child maintenance would be over this period. I need to accept it just won't change, and there's nothing I can do about it.
AIBU to ask you please to give me arguments for myself to just letting it go, forgiving and moving on. Especially if you have been in a similar situation and made peace with yourself over it. I sometimes just get obsessed with the unfairness of it all, at a silly teenage level of "the world is baaaaad" angst. He had just informed me that he's taking them to Disneyland this summer, and I can't even be happy on their behalf, the only thing that I can think of is "had you contributed 50% just for the childcare costs, just in 2022, I'd be able to go take them too". The children are very excited, want to chat with me about it all the time, and I realised that I have developed a very toxic materialistic mindset on the matter.
I also do not receive a single penny in welfare before anyone jumps at my throat.