I only have experience of this from a personal pov i.e. I am currently going through a divorce.
Firstly, the reasons for the divorce are irrelevant - the only reason why people file for adultery, unreasonable behavior etc is because it enables the process to move more quickly. Otherwise you would have to wait for two years. But from a financial perspective it makes no difference why the marriage broke down.
Secondly, there is a difference between child maintanence and spousal maintanence. Your dh is legally obliged to pay child maintanence, and I don't have the exact figures to hand but check the CSA website because there is a starting point but this also then alters according to the number of nights per week your children spend with their father.
There is also spousal maintanence and this can vary esp if, say, you have given up your career in order to raise a family, but the norm is certainly not as high as 69% afaik. Also any spousal maintanence would only apply until you remarried or cohabited with another partner at which point that would cease and your ex would only be liable for child maintanence. He could also apply too the court to reduce this sum if his circumstances changed.
Wrt his pension you could claim entitlement to half of that but bear in mind that that half would be as it stands now not at his retirement age, it would be frozen and half paid to you on retirement.
Now this is all very well but
While you are raising children it is understandable that you will require some level of financial support. However, once your youngest is school age you will be in a position to find workk and begin to financially support yourself. Ask yourself - why would you want to remain financially dependent on someone with whom you no longer seek to have a relationship? Wrt his pension - you have another twenty/thirty years in which to acumulate your pension, doo you really think it fair that you should still be entitled to half his pension thirty years down the line?
My personal view is that while the initial period after a divorce is difficult and you will require financial support to rebuild your life, esp as a current sahm to four young children financial independence should be the ultimate aim. You want this man out of your life for a reason - as long as he supports his children, you should only seek to be "entitled" to spousal maintanence for as long as it takes you to gain your own independence financially. After all, his circumstances may change. He may lose his job or remarry and have other children to support, or fall ill or any number of other unforeseen things. And what then? An "entitlement" can only last for as long as there is something to be entitled to, iyswim.
In my own position my ex has been very reasonable (I won't go into details here as frankly it's not really anyone's concern), but I haven't made a claim on any of his bonuses or his pension as I feel that is just a bit grabbing iyswim. My aim is to build my own business and to gain my own financial independence by the end of the year. People tell me I should be "going after" a lot more, but why should I? As long as he's supporting his child I don't see why he should be expected to support me for the rest of all eternity. I've got my equity from the house etc so I haven't sold myself shourt in terms of division of assets, it just seems wrong to me to expect money for as long as I can get my hands on it. Now I will just state at this point that I haven't made a specific date for the end of the year for xh not to support me, but I wish this to be the case for both our sakes. He shouldn't have to struggle financially any more than I should.