We are human, we tell lies. It depends on whether or not the lie is hurtful. If a wife asks her husband "Do you like my new hat?" He would be a fool to say "I think it's dreadful!". However, if your boyfriend is telling "hurtful" lies, then tell him! Firmly!
In our relationships we might often "fall in love" with a person we really dislike! It happens. If he is a complete liar, then you have to accept him for what he is. Otherwise, drop him!