Airies, these marriages don’t all fail. I know of several cases of intermarriage where after several years, the partner became very interested in Judaism and eventually converted. All of these couples had a chuppah and became active, as families, in the shul. In 2 cases, the converted husbands ended up becoming president of the shul. They daven beautifully – one of them reads Torah as if he has been doing it all of his life and the other often leads the mincha/mariv service.
Soliek, unfortunately you cannot “save” everyone and you cannot take everything so personally or you will burn out. Obviously kiruv is very important to you and you should put your efforts where they may be able to do the most good. I can’t understand why an organization wouldn’t want you. Have you considered doing some work for Jews for Judaism? They are a wonderful organization and have been able to “rescue” many Jews from misguided messianics who have them convinced that their brand of xtianity is actually Judaism. I think you would be a wonderful asset to their work. Don’t be so diheartened. You do the very best that you can and that is all that can be asked of someone.