I have been enjoying the sharing of my wife and previous girlfriends since I first became aware of how erotic it was to consider the woman of my affections a sexual object for other men... I loved the idea that she would be turned on beyond her ability to say no - that her body would crave sex with a man that conventional society would deem to inappropriate.
Once I found that out about myself, I enjoyed exposing the woman I was with either in the car or on the beach, including taking them to nude beaches so I could also witness the displays she would put on when men looked at her naked body...
My wife was the perfect match for me because when we got together it was clear that she enjoyed the attention men paid to her, and though she was very modest from a catholic upbringing, and would never venture outside the norm on her own, she trusted me enough and wanted to please me enough to try things that went contrary to her raising, like going to nude beaches. I was luckier still because she did not deny the excitement she felt being exposed to naked men who did not hide their arousal from her. It was of course very arousing for me to see her become aroused, and in no time I was encouraging her to be as naughty as her inclinations would allow her. She trusted me enough to take me up on it, and boy did we have fun (and are still having fun!)