I have never been a JW and am not only dating an ex-JW (Gadget/Paul), but am engaged to and marrying him in May of next year. At first I was terrified to meet his parents because of things he had told me about the JWs and because of what I had read on this board.
However his parents have never shown me anything but care and respect (his dad even telling me that he looks on me as a daughter - which is quite nice really cos my own dad doesn't show me that much concern). His parents would do anything for us (within reason I guess ) and likewise Paul and I are the same with his parents. Religion per se is never discussed but there has been the odd reference to meetings, talks etc, but not enough to make me uncomfortable or concerned. I do find that I watch what I say a little and I tend not to mention birthdays or Christmas, and when his mum came with me, my mum and sis for my dress fitting, my nerves were on edge every time my sister uttered "oh God", "for Christ's sake" and "oh bloody hell" lol.
Although I don't post often, being a member of this board is really helpful, as for non-JW's, it really gives us an insight into what the life of our partners has been like (or may still be like) and gives us a better understanding of how they tick.
I agree with LT that it will be difficult but I also agree with Cordelia that you shouldn't write him off because you are worried about how his parents will react to you. You might be surprised, but if not, that doesn't matter - you are going out with your partner, not his parents.
Good luck and best wishes
Faolan/Claire x