I love Dag, even though we disagree at times. This doesn't happen to be one of those times - with the information given I would agree, it sounded pretty creepy.
Not to put too fine a point on it, but it's a theoretical
relationship. I would avoid looking for a person to fit into a pre-determined relationship structure. That is really just setting everyone up for having failed expectations. Instead, I suggest letting her put on her big girl panties and do her own looking for her own boyfriend. This theoretical boyfriend coming into his new theoretical polyandry setup might be a tad intimidated by her current partner having his hands all up in the process.
Do as you will, just my personal take to help navigate some of the traps you are setting up for yourself.
I don't team date, so my experiences might not be very helpful for your arrangement. I avoid involving myself in my partners relationships just like I avoid getting involved in my friends marriages... it's not my business and I have plenty of my own fires to put out without getting in their stuff. If they request my input I will, of course, help if I can and I feel comfortable with it.
My preference is to associate with reasonable, self-sufficient, attractive (to me) people who find me enticing and don't have any interest in dictating what I do with my time/body/emotions.
I also like long walks on the beach