There are many swingers clubs in Singapore, most of them private. Although swinging in Singapore is not illegal, few swingers tell family and friends about their lifestyle.
There are quite a few local Singapore couples and expats living in Singapore that are very much into swinging and swingers parties, but they are private about it.
There are two main swingers clubs in Singapore, and another few private swingers groups that have regular swingers parties in Singapore.
A lot of Singapore couples choose to go to Sex clubs around the red light districts in Singapore. The most popular would be Geylang red light district, or Four Floors of Whores.
There are regular private house parties and meetups at classy hotels around Marina Bay Sands area, but they are by invitation only. You can find out more about them by joining swingers sites like RedHotPie Asia.