Well, romanticism doesn't do any good without a receptive audience, so you won't succeed there on this one. Hard to take, but if you didn't see this coming, then she probably thinks you haven't been paying attention for quite awhile now. You keep saying "I want". What you both want now is different, given her attitude. Listen, if you've been together since your twenties that's pretty good but people tend to change over time, especially around 30 and you can't control that. Therefore, someone who was good for us in our twenties may not be in our thirties, and so forth, get it? Consider your relationships like a tree. You both start out on the same trunk, but as the tree grows you can end up on different branches, finally losing touch with each other. That's what they mean by "branching out", and it naturally happens all the time. Cut your losses and move on before your grief turns into self-loathing.