Why do I have to be beautiful everywhere in front of him I like?

First of all, because you care about him very much, you don't want him to see what you think is imperfect.

In fact, you will be very tired and unable to be yourself, so even if you two are together, you will not feel happy because you are pretending everywhere.

So, if he really likes you, he won't mind so much, but you think too much.

Everyone wants to show their best in front of the person they like, which is understandable.

But this is for you to have no baggage, just do what you have to do.