My best[f]riend and I finally [f]ucked

This is my first time posting so go easy on me & sorry for the length :p
Some context – me and my best friend, we will call her Ryan, have been close for four years now; I’m 26 and she’s 24. Her now husband, we will call him Collin, and I have been friends since we were 13. Ryan and I became close when Collin moved away for a year. In the beginning of our friendship, Ryan asked me if I would have a threesome with her and Collin but I never took her up as I was just starting a new relationship.
I knew early on that I was sexually attracted to Ryan but she came off as strictly straight and was only interested in a threesome to make Collin happy. She’s petite – about 5’4, thin with large D breasts that she hides well. I’m 5’2, skinny but very curvy with small perky tits and a big ass.