The concept where all 'love each other equally' in a triad is so strange to me. What does it mean really? It's always up to the person making this guess to evaluate that it's really the case at the given moment. I mean, if you think that it will be easier if all are involved with each other and that there won't be problems like you experienced before, I think this will not work.
Let's assume your former vee would have worked out as a triad. And all were in love with each other. I think that it still needs three very balanced and confident persons to pull this off. Because the possibility for jealousy is even bigger here. If all just works, if everyone is loved 'equally' (how ever one defines how to measure love btw .. ) it is bound to fail. Because one person will always have to do things differently because relationships tend to be different from each other.
For example, the activities one likes to share with one partner will differ from the things she likes to do with her other partner. And that's where the problems tend to start. "Why did you do this and that with B while you only ever do this and that with me?" would be a question that C could ask A in this triad situation. As long as equality is the goal, relationships will be in a tight spot, because they are constantly compared to each other. I believe that each relationship is something that unique and special that it can only flourish if the persons involved accept its individuality. In a triad this would mean, that person A has her own dynamic with B and C and those will differ. And there are bound to be problems if C tries to apply her 'relationships standards' (meaning the way she 'does' relationships) to the relationship of A and B, to measure if it's is equal to the ones she shares with A and B herself.
Hopefully this made sense, it was just something I got from your comments on the situation you had experienced and how you wanted to solve it in the future.
Facts: 30, female, bi, v-type relationship with Sward (husband, straight, mono) and Lin (boyfriend, straight, mono), poly-fi and co-primary.