Anybody else’s kids hate their step parents ?

My son just hates my boyfriend , he’s one years old and screams and runs from my boyfriend and comes to me and hides his face . This man has been in this babies life since I was 12 weeks pregnant was there through my whole pregnancy there when he was born and so on , and he still just does not like his step dad . He doesn’t know his real dad or anything but I’m starting to think my son just knows that isn’t his real dad ... is that possible ?