Is one self required to apply more mascara in the public due to the husband wanting?
The technical answer to your question is that it would depend if the amount being applied is tzniusdik or not. If one’s husband wants her to to go in public in a way that she is not allowed, she is not allowed to do that.
The practical answer to your question though, is why is your husband requesting this? If it is because she is dressing like a “shmata” at home and she dresses up, puts on a sheitel,makeup and a dress, and beatifies herself when she goes outside, then she is causing this situation, because she is not satisfying him at home. A woman should put on makeup, beautify herself and dress nicely and attractively for her husband at home. Then, in most cases he will be satisfied, and he won’t want her to add more mascara when they are in public.