can a girl and a guy be friends?

hey y’all! I go to a Christian University, and today me and my friend (girl) we’re sitting eating lunch. and two guys came over and sat with us being friendly! me and my friend wanted to seek more friends bc we don’t know anyone and these guys were so nice! i have a bf and he got really mad at me for asking if a girl and a guy can be friends.. i say it’s harmless. what do y’all think?