Stressed triangle shit

Maybe I'm wrong, but I just need some help. I'm dating this guy who I met differently than what he is right now. When his fam found out we were official, and taking eachother serious some news came out. "His ex is pregnant" 5-7m pregnant. His ex is his blood cousin, they dated back in June and broke up November... I don't know how to react because I met him without a baby. I have a baby of my own, but my son is 2yrs and he met me w a baby so he knew what he was getting himself into.. But he's having the baby in July and idk how to react, feel, or what to do. It was so random and unexpected that my whole perspective to our things changed. Maybe I should accept him anyways for that, but its totally different, he's still inlove w the girl(my mentality) and all girls know how guys are w their babymoma and this and that, I need help. Cause if it was up to me, ill be completely selfish.