Hi Tony,
 
Thank you for your question. It sounds like your Tempur mattress has lost its support so you are sinking in too much. Which Tempur model do you have? It may be that you do not need a firmer mattress, just a new one with the correct support. If you have found your current mattress comfortable until recently then a simial model would be the most suitable. 
 

 
Have you slept on a traditional mattress? We have found that customers that are used to the flat sleep surface of memory foam sometimes have difficulty adjusting to the tufted areas of a traditional pocket-sprung mattress. A separate mattress topper can help to even out the sleep surface which will eventually flatten out.
 

 
If you like the moulding sensation of memory foam then a latex mattress may be more suitable. Memory foam is very heat retentive. It requires body heat as well as pressure to be able to mould to you but the heat does not dissipate and is retained within the mattress. Latex only requires pressure to be able to mould to you and it is more responsive than memory foam along with being more durable. We only have one mattress that has latex as the comfort layer, the Origins Pocket Latex 1500, but at your light body weights, this would give both a firm feel. I would recommend a medium-density latex from a company called Latex Sense.
 

 
Given your body weights, the medium spring tension will provide the correct level of support. We do not offer a soft spring tension other than as a bespoke item which would not be covered under our 60 day love it or return it guarantee.
 

 
I would recommend a medium feel in the upholstery layers so that you have cushioning in the top layers and your wife will have the more supportive layers underneath to so that she doesn't sink in too much as a front sleeper. I would recommend looking at our 2 most popular models, the Artisan Naturals and the Origins Pocket 1500 which both have a true medium feel in the upholstery layers.
 

Please note the soft spring tension has been discontinued since the making of the video.
 
I hope this helps and if you would like any further information or would like to discuss your individual needs please do not hesitate to contact the office on 0161 437 4419.
 
Kind Regards
Michaela