I never had monogamous relationships, only since a year or so with the gf I have since 7 yrs, she wanted to be exclusive now... I dont mind, I had a good run and she is the one...
I remember my first threesome, I had planned to meet up with a girl from school on a friday night, I was sixteen and still living with my grandparents, we were going to go to a party.
She brought a friend, a lovely mulat girl, but I didnt show much interest in her since originally I wanted to have sex with the girl I already knew.
The girl from my school got kind of drunk in my bedroom, where we were pre partying, and she more or less passed out on my bed.
The mulat girl then started to hit on me and this lead to sex which lead to the other girl joining in...
We didnt went partying anymore...