I think the swinger lifestyle is just more suitable for some than others. I personally have a hard time being myself when I'm dating a girl who acts very reserved and frigid about sex & any kind of sexual expression. It makes me feel uncomfortable. Something I learned about myself is that I may not take it as far as swinging, but I am definitely feel more comfortable when I'm in a relationship with a girl who is open-minded and more liberal minded when it comes to sex life.
I always still put a hugh emphasis on getting to know that person first, establishing that deep connection and trust, and also being responsible and clean...disease free. I have an issue wih swingers who show a disregard for that. The ones that don't disregard and do take all the precautions to be clean & responsible about it, I have no issue with.
For example, if I was in a relationship & we considered swinging with a certain person, I would personally have to require all 3 of us to go to the doctor together and take the STD/AIDs together in order to even consider it. I would have to hear it out of the doctor's mouth in person that everybody is clean & disease free.
Now how many swingers actually would or do show that much responsibilty? I would guess very few