Our cuckold journey was a very slow process. I encouraged her to cuckold me for many years before anything ever happened. In the early stages it was just fantasy talk, for example during foreplay we we would talk about her being with other men which would get us both turned on. At first my wife was reluctant to do anything at in real life, but eventually, she felt comfortable dancing, talking and flirting with other men. Eventually this did result in her kissing with a guy one night which she told me about after we got home. This really got us both super turned on. She has told me that kissing another man was probably a big turning point in her decision to ultimately cuckold me.
What is a bit weird about the whole thing is that you and your wife never talk about it. It's just something she does -- and she has never made any effort to hide what she's doing. So, for example, you're fully aware (because she enlists your help with packing for these trips) that she takes her sexiest lingerie and bikinis with her. And her sister posts pictures on social media (facebook and instragram) of the four of them together, and usually some of your wife and her "cabin mate" together, including pics of her with his arm around her or with her sitting on his lap, and pics of them kissing -- and sometimes with captions referring to your wife and her cabin-mate being affectionate before heading to their cabin for "another hot night together".