> All female partners have said that they don't care about my weight, and some actually like some belly to rest on.
Contrary to popular belief by men, women are very visual. They say things to each other like 'How do I get the guys I am attracted to to notice me?' The problem we have is that when guys ask why we reject them we can't give any sort of honest answer because the men will start to debate our answers. Combine that with the fact that they are stronger and can physically assault us and many men don't get this important signal and are left with the impression that how they look doesn't matter to women.
Some men do eventually realize that their looks do matter when it plays out in the office.
If you want to look at it from an evolutionary perspective who should I choose for a mate: Someone I can see is strong, fit and in shape or someone who isn't? The lack of muscle definition hints of possible low T in the same way that overweight women hint that they are possibly already pregnant to men. Is that skin issue genetic or from lack of care? Who could better help and protect me and my offspring?
Sidenote: The fact that men don't take care of their skin is such a weird societal issue. Taking care of your skin at the basic level is an aesthetic choice like taking care of your teeth is. It shouldn't be gendered. Everyone should take care of their skin and wear sunscreen, it is your largest organ.
A man that is not overweight, has some muscle definition, showers and wears clothes that actually fit his body is instantly more attractive than the countless men that don't.
To add one final little bit to your original statement:
> All female partners have said that they don't care about my weight
We never want you to say that you care about our weight. We want you to care for who we are, not for what we looked like when you met us at 19. One day we will be 60. We also will not tell you what you have to do with your body. We have had a lifetime of men telling us what we should do with ours and know how negative that is. You can weight what you want and if you are our special someone we will not care, but we will be more attracted to you when you are not obese.