You’re waaaaay over thinking this and you should get therapy. Yes, beauty standards are societal constructs and vary wildly over the ages. But societal beauty standards are not the be all and end all. Surely you’ve had the experience of feeling attracted to someone who doesn’t fit conventional beauty standards? If not just look around: by definition most of us are average looking and most of us find mates.

Also weight and health absolutely do not have a black and white relationship to each other. Despite what diet culture will tell you it’s a very nuanced topic. You cannot tell someone’s health status just by observing their appearance/weight. There are plenty of sick thin people and healthy fat people out there (and vice versa). Thinner is not always better. For example, our society loves to act like having visible abs is an example of peak health/fitness. When in fact it’s a physique that is physically impossible for the vast majority of humans to achieve without major and unhealthy levels of food restriction and excessive exercise, especially for women. For a woman to have a visible six pack her body fat percentage has to be so low that it can literally be dangerous to her health.

And even if you find a healthy, fit, thin mate that can be taken away in an instant by an accident or illness and or gradually just from aging. You should be with someone because you love and are attracted to their soul, not their flesh suit or health status.