self awareness in relations?

i’m having trouble hooking up with people lately, whether it’s a partner or a random, i tend to go for people i’m not even attracted to as it makes me feel less insecure during sex.
i’m not fat, i know that, but i know i’m not skinny, and it makes it very hard to go for people (relationships too) that are attractive or fit.
idk what to do, this is also coming from someone who usually doesnt care what other people think. btw— how do i stay hooked at the gym