I'm sorry that you're still hurting over this.
Part of what makes my situation liveable is that I understood, early on, that affection develops with different people at different rates. I didn't *want* that to be the case... I wanted my lover's lover to want me emotionally as much as I wanted him... but I did a lot of reading about other people's experiences and their advice, and I saw over and over again variations on the idea that you shouldn't expect a three person relationship to be perfectly equal. I wanted a triad but ended up with a vee, and I've come to accept that a vee seems to be more likely, more easy, and more natural. Natural in the sense that it is hard to love two people quite the same, and not very likely that those two people should happen to also love each other. Love is just such an individual thing.
All of that said, I have a good friend who's currently in a triad that's been working out quite nicely, so I'm certainly not going to say it doesn't ever happen.