You had something wonderful and now it's gone, and you're mourning that loss. Does that sound about right?
I can't say for sure of course, but it doesn't sound like there were any warning signs for you to "miss." (Of course, if there were, you missed them and therefore didn't report them here... catch-22) It's reasonable to believe that after 15 years of being poly, they would have worked out this shit.
The problem is, if they're still using vetoes after 15 years, there's a good chance they (she?) have a lot of shit that they've never actually dealt with, but rather bypassed by just shutting it down whenever it got "hard."
Breakups aren't fun. There really is a process of mourning to go through when you lose someone. Veto breakups are probably extra hard because you know it wasn't even your own partner who broke up with you.
I don't like vetoes. We don't use them. I don't date people who use them, at least not if they allow them to be used after relationships are established. For example, Auto and her hubby have veto agreements for PREVENTING relationships before they start. But if he tried to make her break up with me now? She'd tell him to go to hell.
Gralson: my husband (works out of town).
Auto: my girlfriend (lives with her husband Zoffee).
The most dangerous phrase in the English language is "we've always done it this way."