Am I wrong?

Long story short my bd and I have only been together since Oct. and we have a baby otw due this Oct… I haven’t met his parents yet but he says he wants me to soon. He has a child from previous (3 yrs) and yesterday was his mothers bday party he said I should’ve been there but today I see pictures of all them and his ex babymom was there… am I wrong for feeling some type of way I don’t understand why she was there..