Jealous...and feel like shit for it

My wife and I raise her 4 year old daughter and have been doing so since she was 7 months old. This baby girl is my world but I feel so jealous when my wife talks about her as a baby, or how close their bond is and just now she pulled out her baby box and I saw the positive pregnancy test and I haven’t even gotten a faint line before . Like she didn’t even want to get pregnant...here I am trying so hard and nothing. I feel like a bitch being so jealous of my own wife but i want so badly to be as lucky as she was....