I learned that I will make decisions about 'us' without talking to my S.O. The last solid relationship I had before the lovely young woman I am currently seeing was my last high school girlfriend. We had been dating for the last 3 months of my senior year and she was a sophomore. I decided, a few days after I graduated, that WE wouldn't work while I was at school. I thought of it at the time as wanting to be fair to her, but if I really wanted to be fair to her I would have discussed it with her, rather than make the decision outright. I must guard against this.
If you decided "we" wouldn't work because really, you didn't think it would work for "you," then I don't think it was really a decision that needed her input. If you decided "we" wouldn't work because you really didn't think it would work for the two of you, but it was a circumstance which perhaps could have been affected by a conversation that the two of you would have had about how to resolve those problems or prevent them, then yes, her input could potentially have changed your decision. The decision to breakup isn't always one that needs the other partner's input, that's all.
The latter in this particular case. I made all sorts of assumptions about what would or would not be 'fair' to her, what her opinions 'obviously' would be. True. I would add that the cases where the other partners input is needed is when things are going well, but there are significant concerns about the future.The decision to breakup isn't always one that needs the other partner's input, that's all.