Baby mamma drama??

Ma
:( ok so my boyfriend has a baby mamma and i just fill like crying when talking about this but I really need someone to talk to cause it makes me so sad to the point I get mad at him for no reason and I say to my self that I cannot do this cause I really do fill like that sometimes it hurts me that I will never be the first to have his baby  like she was his one night stand and she became pregnant but like idk how to explain this is anyone in this same situation??