Don't know of any books or films on the subject, we were married 15 years when the wife went with her first "other guy" and it was her first other guy as I had taken her cherry when we were both 19 so it was a big BIG step for her.
We started off talking about sex with others when we were having sex, then I met an old mate that I went to school with who was in a nudist club with his wife and youngren which we went to with them and ended up joining, there we found an underground swinging movement which we were on the edge of, and it happened which opened the door for 25 +years of swinging, swapping and M F M 3/somes, we have now been married 45 years.
The only suggestion I can give is that you get your wife to start looking at sites like this one, keep putting opportunities in front of her, but never ever try and push her into anything she is not ready for, always leave her a way out if she wont's out.
