The priority is housing children under 18 but young students over 18 aren't irrelevant and it is reasonable for them to have a base even if they are away at university during term time. Your housing need is therefore to accommodate 4 children and yourself adequately. That has to be balanced against the housing needs of your husband who requires somewhere suitable for the children to have staying contact.
When the former matrimonial home is bigger than required it often has to be sold to release equity to enable both parties to rehouse. If the house is worth £190k and there are 4 children it is unlikely to be larger than required to house them and yourself. Therefore the considerations are local property prices and both parties mortgage raising capabilities. Some mortgage lenders will take Working Families Tax Credits and maintenance into account when determining the amount they are prepared to lend. The aim is to raise enough mortgage to enable some equity to be released so that there is something towards a deposit for a new home for your husband.
If you can't raise enough mortgage and there is no other way of keeping a roof over the children's head your husband could maintain an interest in the former matrimonial home in the form of a chargeback which is paid when certain conditions trigger a sale. You would be responsible for meeting the mortgage payments. There can be different triggers but the usual ones are the youngest child reaching 18 or finishing uni and the parent with majority of care remarrying or dying. Beware though that there are disadvantages in this arrangement, in particular being tied to your husband for many years until a sale is triggered and the possibility of not being able to raise a mortgage for the usual 25 year term to rehouse yourself.
The other option would be renting.
As others have said your husband would be liable for child support for the 3 younger children whilst in education at 25% of his net income minus deductions for overnight stays. There is a calculator at the CM Options website that will give you a rough idea of the amount. It's worth checking out state financial help at www.entitledto.co.uk - if you work 16 hours or more a week you might be surprised at the amount of WFTC you will get.
Spouse maintenance isn't very likely because when child support and state help are taken into account there isn't a huge discrepancy in incomes. If you have a larger slice of the capital or your husband has to wait until the house is sold to realise his share his monthly outgoings will be more leaving little or no disposable income to pay SM.
Divorce settlement are treated case by case and I think it is a good idea to see a solicitor early on to find out where you stand and what options there are given the specific details (for example you don't mention pensions and they have to be taken into account as part of the overall circumstances) even if you then decide to negotiate between yourselves or with the help of a mediator.