shundaroni,
I just don't even know what to tell you, other than thanks for sharing your own experience. Mine has a been a little different than what you may be envisioning. BF and I have gone through multiple changes in the time we have been together. I have been in better shape than him for several years at at a stretch. Didn't really change my attitude about him before.
Aside from the occasional amusement obtained by flirting with guys (which is all going to fade with age and time anyway), I'm not really interested. There are just too many weird and awful people out there, once you get to know them deeply. I've got a guy that I know pretty darn well, and I know him to be a good guy, who understands how my mind works and shares alot beliefs and values with me. In fact, he is the only guy I've ever known who could understand how my mind works. In other words, I'm not interested in "trading him in."
...But that's not gonna stop a bunch of strangers from trying to "fix" me, is it?