Everything is so difficult at the moment - you really aren't alone in this.
Is there any way you can separate yourselves at home more? Sleep in separate rooms, don't share plates and cutlery, be really really strict on hand washing and no physical contact? Could you even move out somewhere else so you can keep working? Or could your partner go stay somewhere else? I know that's not ideal and potentially very lonely.
There's also stuff in place if you have to stop working - Statutory Sick Pay for people like yourself who might need to stop work because of someone in your household self-isolating or Universal Credit.
https://www.gov.uk/government/public...ed-by-covid-19
Don't know if that's any help at all.