Personally, the “conflict” sex-vs-religion always confuses me. Isn't sex a necessary biological need? Maybe I understood the whole thing wrong.
Not talking about lust. Will I go to hell if I am looking at some guy on the street and thinking how I'd fuck him? Since youth, we have been taught that sex between two lovers that are not married is bad, that sex before wedding is bad, and basically, everything that is sex-related is bad. But, where did this mentality came from? Why is sex bad? Should we use sex just for reproduction purposes?
But let's talk about swinging and religion. So, this means that you are having sex outside of your marriage and it is considered a sin. Did you ever think that swinging means breaking the wedding vows?