I know it’s strange that he wore clothes like that, but that by itself is not a valid reason to reject someone. If along with the clothes, you have an issue with his views or his sense of humour etc. then it’s fine to tell him you’re not interested. But don’t let the clothes be the only reason keeping you from giving him a chance.
Also, it sounds like you need more time getting over the previous guy and after that you should be more open to people that come your way. Try to work on yourself first so that you don’t make the mistake of becoming super emotionally dependent on someone who cannot commit to you. Your true happiness is in your own control.