This really deserves a long answer, but you're going to get a short one. When we got married, W weighed somewhere in the 120 range and wore a 12-14. She started putting on the weight after a couple of years, but it was gradual. The only other time I can give you an accurate figure is when she was PG. When she first went in, less than a month into the pregnancy, she was 230lbs. She gained 6lbs. during the pregnancy. Since then she dropped to around 190~200 and has pretty much stayed there. She now wears either a 22W or a 24W depending upon the particular garment.
Like most people, she looks better when she’s thinner. But she was no less attractive to me at any weight.
Since I’m not her, I really can’t speak to her level of desire. All I can do is comment on the outward signs. W was at her lightest when we were first married. As you well know, for the first 11 years plus our sex life consisted of approximately monthly encounters where I went down on her and she (maybe) gave me a half-hearted HJ. IC began at her absolute heaviest. The most desire I have ever seen from her has been this past year. All of it at the 190~200 range.