Usually a separation means that someone needs to find a new place to live. The New York Times has a useful tool for looking at the long-term costs of renting versus buying. https://www.nytimes.com/interactive/2014/upshot/buy-rent-calculator.html
You may find this tool useful if you are looking for new accommodation for yourself, but it can also be useful for negotiation purposes. Figuring out how to structure a settlement to meet both former spouse’s needs can be the hardest part of resolving a separation or divorce. Even if legal entitlements are clear, it is foolhardy to expect someone to accept a settlement that leaves them unable to meet their basic expenses. And if someone is fixated on the need to purchase a new home, this tool might help to adjust that expectation.