Is it okay if i ask to be left alone?

my boufriends son, he always is saying "i love you" and i dont even say it back to my boyfriend, he also just grabs my cup of ice cold water and drinks it up. he licks his plates, and kisses me on my head, cheek, and i dont feel comfortable with that. when his dad comes home he pouts all the time. and i am so annoyed, i dont know how to tell him to leave me alone or how to teach him boundaries.