HELP?! Could it be my boyfriend's baby??

Okay to start off this is about him possibly cheating again. He was in contact with this girl for over a year until I figured it out and he supposedly stopped talking to her and told me he only ever talked to her and never was physical. Then I got pregnant (accident) and I noticed about a month or so later she was pregnant too but she had a boyfriend so I didn't think much of it. Then the baby is born and it is a spitting image of my son. He's very very blonde and very very blue eyed. That only raised some eyebrows with me because the girl is half black, dark haired and dark eyes and her boyfriend who is supposedly the dad is dark hair and dark eyes. Her mom is dark haired and dark eyes and her dad is black so I'm just baffled her baby came out looking like that and the more the baby grows and gets older, the more it looks like my son and boyfriend. Do I just sound crazy or is it possible he cheated?!?