I didn't realise a reference to vanity sizing would cause so much fuss, and I am sorry that it did.
And am now wondering if this is to do with age. I can remember the days when dress size was regulated and standardised, and so "see" sizes as those standard sizes.
But that changed in the 1980s. Up until then, a US size 10 (UK 14) was 34.5 inch bust, a 24.5 inch waist and a 34.5 inch hips. Today, there is no standard size 10, and the smallest size 10 (as quoted in NY Times) was 35.5 inch bust, a 26 inch waist and a 37 inch hips. "And in many cases, it's almost an inch larger than that". The British sizing followed the US with deregulation, and this is when 'vanity' sizing emerged here too (for nabbing market share of course).
Though if there is no standard, then dress size is even less of an indicator of size/shape/likely weight, let alone health.
OP: if you are beginning the think you need to lose some weight for the sake of your health, there are loads of resources that can help you.
But it won't fix your marriage. Mismatch of libido can be a huge problem. It can ebb and flow in any marriage. In good relationships, once one partner recognises that things are badly out of kilter, then both work together to build things back to a situation both are happy with. And that takes good communication, willingness to grow, and real commitment to making things work for both without excessive demands on either.
You say he is a good husband in all other ways. But what is communication like between you overall?