It depends on the definition of " attractive" .. if you mean " shaving, cleaning, washing " then I do this even if I would live on a island alone.. but if you mean style.. I actually care more about it if I am in a relationship than if I am single.. because I want a guy to fall for me for who I am normally and not for the stylish, trying to be cool me.. however, if I am in a relation , I have to put some more effort to make him want me even more.. not just for my personality , but also because I do know how to look wow!.. but still, I don't overdo it .. just every now and then
Looking good should NEVER be about the other person. You should care how you look for you. BUT, if you care about the person, I would try to be presentable - at least be clean, teeth brushed, hair combed, washed outfit. It shows that YOU care about YOU. Which is far more attractive than doing it because you think someone else wants it.