Having a baby with a man that already has one

Having a baby with a man that already has a 5 year old... Okay. When we first go together I knew he had a kid... What I didn't expect was to feel so.. Resentful? To the best of my ability I have his these feeling thinking (your over acting) (this will go away) it never went away! DO NOT GET ME WRONG I love her! Just like I love him! Like she is my own.. But she isn't and I wish she was... I wish I could be her mother (not trying to replace her mother lord no!) But only wishing. Is it wrong for me to wish that? Its hard because now that I'm pregnant it seems... She gets brought up a lot his 1st babymomma.. And I dont know how to control my actions. Like this morning

I got the book what to expect while expecting he said "oh that's a good book ___ she read it when she was pregnant"

Oh I jumped down his throat.. I couldn't help myself.. I know I can't blame the hormones on everything but how do I deal with this?!

When we announced we was having a baby she said "your baby isn't going to be loved like mine" yours is 2nd to mine" horrible mean stuff.. I would never say!