Accidentally bisexual

We tried a swinging club but didn't like the crowd... Fortunately we met this wonderful couple. So different from us, as the husband was very tall and the woman dark-skinned and very busty, but we clicked instantly. We decided to meet again at their place. The house was simply furnished but with delightful lighting, birdsong was coming in from the open windows. We starting chatting, then cuddling and kissing... The men went out to have a drink in the patio. When they came back, Julia and I were kissing, totally undressed. They watched us for a while. Then magnetically the two men were drawn to one another, and starting touching each other. Totally unplanned but with this intense vibration, it was our first bisexual experience (and theirs too, they confessed).