Am I too big?

I'm seriously worried here. My girlfriend and I have been dating for about 6 months or so and have only recently begun to have sex. She has only had one sexual partner before me who was smaller. I'm about 6" long and Idk my girth... I'm about 2-1/4" in diameter at the thickest. (Just the tip)

We've had sex less than 10 times and all but two times have been painful for her. She's plenty excited about it as there is tons of foreplay. She's plenty wet when we start. This last time however we had to stop almost immediately because it was too painful and she is starting to feel like she cannot love me completely. Like she doesn't love me enough... (Story in her head being that if she loved me more then her body would magically work.). There's absolutely nothing wrong with her body

She really is the best thing that's happened to me and it's starting to scare the hell out of both of us...

What can we do?