If only I were as eloquent and brief as the Haiku Master. But alas, here we go.
There are few things that will destroy a traditional marriage faster than exchanging body fluids with others outside the marriage. Except in rare circumstances the jealousies, insecurities, emotions, etc this will cause will destroy the trust, sanctity and security of the marriage. Why would you want to expose what you characterize as a very happy and secure marriage to try the body parts of strangers? There are some who post in this forum who support multiple partners but the vast majority will say no.
A drunken promise to uproot your life after 5 years so you can leave your family, move to a strange place where he has no family, no past and an uncertain future. What are his ties to Berlin that he wants to move there? Or is this really just to get away from your life? Need to dig deeper to find out why. And Prudie is right, all this should have been worked out before the marriage when heads and hearts were clearer.
Find the former roommate, face the music. Not all that hard if you really want to. Donating the money to charity will not clear the conscience.
Either use the delete button, or block email from these folks. You are not going to change them, so decide if you want to continue to receive email from them. Might want to let them know you are doing it and why.