Latex mattress for sleepers of different weights

Hi,
I've been given your details by friends who love the mattress and service that you've provided.
I wanted to replace a 15 year-old cheap sprung mattress. I have tried out various mattresses in various showrooms and
decided that I really liked the feel of latex mattresses - after having tried some Yanis beds. I hated memory foam beds.
In the end I decided to get an Eve mattress because of the 100 day guarantee. When this arrived I realised that the eve is
much softer than I thought I wanted a mattress to be (I thought I liked firm mattresses). However, after sleeping on it I
realised that it's just about supportive enough to be comfortable (maybe a little more support would be nice) and I
actually really like the feeling sinking into the mattress a little.
The problem is that my partner (who is 22 stone) really doesn't get on with the mattress; in the short period of the trial,
the eve has stopped recovering - it has a permanent on his side of the bed.
The eve is therefore going back and I wanted your advice on what mattress would be suitable. I would be tempted to get a
more expensive latex mattress but I weigh 14 stone, so there's a significant difference in our bodyweights. What would you
recommend for the difference in weights?