To be more specific, "bros before hoes" refers to a man prioritizing the relationship he has with his friends above his relationship with his girlfriend. "Hoes before bros" is the other way around.
Either way, this phrase is degrading toward women, and any guy who doesn't make his girlfriend his number one priority (with exception possibly to academic success) doesn't deserve her.
what a real man would say..
bill: lets go fishing.
joe: i cant i have to take jill to the store today.
bill: dude bros before hoes..
joe: no, there is no "bros before hoes" anymore im in a relationship.