I don't know and I'm faced with something just like that right now as as matter of fact. It might sound mean or selfish but try to think about yourself, if this change, if leaving this person is the best thing for you to do, you can't hold yourself back. You'll only end up resenting that person later, and the longer you're with him/her the more it'll hurt when it has to be over, the sooner you end a doomed relationship the better the chances of staying close to that person.