How to Help My Daughter Accept My Boyfriend

I've been dating someone for almost a year and have very very slowly introduced my 8 yr old daughter to him. We are now at the stage where she understands that we are a couple but is torn between liking him and feeling resentment toward him.

My partner is willing to try anything to build a relationship with her. He is patient as well. I'm just looking for some advice on how we should tackle her mood swings and periods of non communication, attitude and frustration.

She has become very protective of her father and wants to spend more time with him. I don't want to lose the close bond we've always had. I don't want her to become distant or withdrawn from me. Can someone please help?
Thanks.