Should I worry about having kids with my boyfriend...?

He and I have been together for almost a year now (in august) And the thing I want to ask is... this is really embarrassing btw, like I know no one knows who I am, but still... He likes me to call him daddy... yah. I mean he is like 3 years older than me, lol but he loves it! He like sends me the links to daddy and daughter porn through email, lol. We have shared lots of secrets with each other, one time ( months ago) he told me that one time he accidentally saw his little sister masturbating, and he got turned on. She is one year younger than me, and I got the impression he didn't think it was a big deal because they are not actually related. (they were both adopted) But still, to me its sort of weird since they have had a brother-sister relationship practically all there life. I asked him if it was because he is sexually attracted to her, or if it was just the taboo idea. He wasn't sure. =( I mean that was awhile ago, and before me and him really got into a deep relationship, before we started saying we loved each other, before we couldn't be apart for more than a day. And we haven't gone all the way... lol if that means anything, we just fooled around.. I'm not gonna get into the dirty details. =P We talk about the future from time to time, and he wants kids with me. He said three, lol I'm not sure if he said that because he knows thats my lucky number, haha but anyways... I mean I know that theres a difference between someone's sexual side and there morals. And I know he has good ones, but there is a small part of me thats not sure if he would ever think of our kids in a disgusting way. He is hard to read,trust me!! I love him to death, and I my sexual fetishes or whatever aren't so innocent either, lol and I know what turns me on necessarily isn't something that I would ever do for real, or have the desire to. What do you think? Do you think I am kinda freakking out for nothing?