RTFT people, it's not OP making the judgement. She is being being judged by her ex and is seeking reassurance that his opinion is unusual.
OP, my ex used to be the same. He controlled all the money and treated me appallingly. As a result, a) couldn't afford to make an effort and b) just didn't give a shit, I was so miserable.
I remember sitting with him and his family in an airport, fully made-up with a brazilian blow-dry and fancy clothes and him going on and on about how I should always make the same effort instead of lounging around in misshapen jeans and sweaters with my 'bad skin' on show. He'd only allowed me new clothes and make-up because we went shopping with SIL and SIL invited me to the hairdresser with her. It sunk in, that day, that his goal was to belittle and humiliate me to keep me in my place and it wouldn't have mattered what I wore, or how 'pretty' I looked, he'd have found a way to put me down.
Fast forward a few years and he still tries it, even though we're not together anymore and my new career kind of demands I make an effort (I'm training in the beauty industry). If there is anything wrong with my hair or make-up, he will fall over himself to comment on it. Last time, it was grey roots coming through. He still tells the children I smell and don't have good hygiene and asks them if anyone at work has mentioned it
If he finds out I'm going to a job interview, he'll email me to remind to wear clean clothes, bathe, clean my teeth and cover my 'bad skin' and 'grey hair'.
The problem is not with me, it is with him and nothing I do or don't do will change his opinion. The same applies to your ex. If he wasn't picking on your appearance, it would be something else. Don't give him any headspace. Normal people, the kind of people you want in your life, don't think like your ex, as demonstrated on this thread.