By Kayla Kibbe So you and your partner want to have a threesome. Congrats! Sounds like you two are an evolved, open-minded couple with a healthy sex life who have done the work to ensure you’re both ready for the mental, emotional and physical impact of welcoming another person into your bedroom. (And if you haven’t, please go do that; I recommend starting here.) Now all you have to do is find a third. Just kidding; that’s the hardest part. I don’t mean to scare anyone off their (certainly very attainable!) ménage à trois fantasy, but if you haven’t started looking for a third yet, I’m just wa…