Regard the following sentence.
Oh, you can't make it? That's disappointing.
It's clear and to the point but it also expresses a certain portion of negativity of the experience. I'd like to use another word that will lower the negative connotation. It's still supposed to be there but not as the main flavor.
Instead, I'd like to feel the recipient included in my "pain" and not feel as the root cause of my disappointment. Please note that I know how to explain in in a next sentence or two but this question is for a single word or at most an expression.
I'd like to cause the recipients empathy for me feeling dismissed and ignored as I'm disappointed that, despite my efforts to accommodate the other's schedule, they won't attend. They are indeed to blame as the main reason but I want that to be disregarded (or at least not pointed out by me explicitly) and focus on my (or rather our unhappiness).