As for dealing with her, if she's going away in a couple of months, enjoy the remaining time with her and then move on when she's gone. Promises of faithfulness are all romantic and mushy, certainly--they're also naive and impractical. If you're both still interested when she returns, great, until then, get on with your life and find more love.
Originally Posted by Tomte
The situation with my friend is different. He knows that I know what he did and he doesnīt have a clou about my poly thinking. In my community I canīt just say, donīt care. My image in the group is not in line with this reaction. And it could lead to further situation of disrespect. He absolutely disrespect me with that what he did and this is hard for me to handle too.
If you feel you really have to respond, then respond. I can think of many different fashions to respond, depending on what sort of response you'd like to get. They range from removing him from your life without comment to leaving him unconscious and bloody for the slight (and I'm unlikely to seriously consider the latter these days).
I will say that having no response to the whole thing can also send a message.