I have problems with synthetic mattress fibres

I have problems with synthetic fibres, and generally avoid clothing that is anything but cotton or viscose...possibly this is something that would affect other people. At the moment I am starting to seek a replacement for our double bed. My husband likes soft mattress..i need a firm mattress, so obviously two single mattress beds would be ideal, but we have problems with lack of space as our bedroom is rather small. However, just started looking...both in our 80's. I have heart issues and quite an imsomniac, so need to take care where a new bed is concerned.Need to sleep.