Is a Threesome Right for Me?

A 6+ year relationship ended early last year, and recently i’ve moved toward becoming “official” with one person after spending a year on my own, exploring, etc….She’s very sweet and we get along great and we have a mutual friend whom i have always been very friendly/flirtatious, but nothing has ever happened. Lately they go out on weekends and talk about me…. I’m just wondering if this is dangerous territory for me, despite the potential awesomeness that could (and most definitely would) ensue. If this turns threesome-y, I want to know potential dangers, etc…I don’t need to do ANYTHING to make it happen, I’m asking you basically if you were me what would you do?