But this, I assume, isn't child maintenance if your eldest is 20? Even if it is, CMS minimum is about a quarter of someone's net income which, when you also have to buy clothes for when they're at yours, pay for travel (360 miles, twice a month in my case plus holiday pick ups - and no, I didn't move away from them and yes, I did fight the move away through Court, for all the good that did me), pay for a roof they can come back to, food they can eat etc, isn't insignificant. It's also tax free for the recipient and doesn't affect any of the benefits or tax credits they might be eligible for.
I'd also forgo any payments from her to have the opportunity to reverse the situation and have my kids at home as often as she now does, but that's by the by.
Yes, I agree that women don't screw men over every time, but the general rule of thumb seems to be to try for around 70% of any equity, assuming they were married. That generally doesnt leave the (usually a) guy a lot to sort out somewhere to live with. But maybe I was just unlucky.
If the house is too large for you to manage, or require, surely you can sell it once the divorce is through and buy something smaller? He can't force you to stay once the deeds are yours. A pension's great in theory, but he won't see the value of that for a few years yet, I assume, and unless he's lucky enough to be on a public sector or one of the very few final salary schemes left around, his pension pot will be at the mercy of the stock exchange. He may well get a fraction of what it should be worth in the end. IMO, these days you're better off with property.