Osteoarthritis and can not find a comfortable sleeping position

Hi
I am 5ft 1 and weigh around 8 and a half stone, my husband is 6ft 1 and weighs around 12 Stone. He also has Osteoarthritis and struggles to find a comfortable sleeping position. Is it possible to buy a split mattress made up of different sides - one soft, one medium possibly, to accommodate our different needs?
Many thanks
Kath