Between 28 years on and off . Had a very vanilla partner in middle of 28 years for 14 years. She was Very very vanilla as far sex but loved naturist holidays nude swims etc
I male half, in 1999 I had a couple of meets with a couple so my first 3 way and experience of the lifestyle, just never thought of it as swinging. Then I had a fwb who had an interest in swinging around 2005 so either 25 or 19 years.
The wife around 12 years we met swinging