Hi I'm a step mom, my husband and I have been together for 8 years married 5 years, share a almost 3 year old son and he has a daughter of 11. She is a sweet kid, a bit lazy and does nothing except watch tv all weekend.
You cannot expect your partner to love your child as their own, but give him the chance to build a relationship. I have the problem where my parents inlaw spend most of their time looking after my step daughter (by their choice) and they interfere with my husband and I. They forever fighting with my husband about his daughter and he is a good father too her, then he comes home takes it out on me and also tells me I have to love his daughter like my own.
Also if you have a conversation with someone else and it has his daughters name in it, he thinks the worse and then it just causes a huge fight and with all the choking a person eventually despises the thought of the child being around because of the fight it might cause and its not even her fault.
So don't force the relationship it will happen on its own if you love eachother enough you will work through it. Dicipline is a key though, no dicipline, no respect, no love.