Originally Posted by DustimusPrime
My fiance thinks right off the bat should be natural and acceptable to start hanging out as a group of three.
Ugh. I wouldn't want to meet a guy's partner before I've determined whether or not I am even interested. It would feel too much like an audition. If I want proof that she consents to his dating others, I'd be fine with an email or phone call from her, or some other proof like her online dating profile.
Also: why does she want to hang out
as a group of three? Where did she get the idea that that was supposed to happen? Are you looking for a gf for her as well? If you're dating separately, date separately.
Introduce them when it feels like there is potential for something to develop, if you think you want to continue seeing these woman. Also ask when they would feel comfortable to meet her. Sometimes an introductory email is enough of a "meeting." Your fiancée (you are the fiance, she is the fiancée) doesn't need to befriend them. Although some of your new love interests might like to, it is not required that metamours get along and become chummy. All that's needed is polite, respectful acknowledgement. If she is having a fit about this, you both need to sit down and come to some agreement on this point that feels comfy and natural for both of you.