I relate to this completely. My new significant other did this to me twice in one weekend. I know he has some obiligations, and he said hopefully next week (he has a child he watches). I don't wan to be selfish or anything, and I accepted what he had to say gracefully. However, on the inside, I get angry and very hurt when my expectations aren't met.

Usually, I try to back off, but the temptation is usually strong to text that person a few days later (if I haven't heard from them), just so they know I'm not mad at them and that I want to keep the relationship. However, when people back out of plans multiple times, I usually let them be the one to initiate the plans. Nothing wrong with a friendly "hello" in between, but if their lives are that busy, it's up to them to make time for you. If they don't, it's time to re-evaluate the friendship or relationship....not necessarily cutting it off (although that might be the solution in some instances), but a sign not to rely on them as much and find other things you can do.

I do think Bipolar plays a role in those of us to have the tendency to come up with great plans and be a little idealistic when hypomanic (or manic), so trying to stay grounded in reality is important. Sometimes that means med changes, but lifestyle changes, therapy, and just learning ways to cope can make a big difference. I wish I was half way there yet, but I'm a work in progress!