fm - Live your life, enjoy the new guy (if you really like him), keep dating and don't worry about choices or what will happen when he comes back. I did the same thing - what if he comes back when I'm with December guy. Somehow it just all works out. If there is a choice to make, it will be clear.
I'm not trying to give you false hope - but - I thought my relationship with SM was over 100 times. I even remember saying what you said to kiki. If you look at the reality, it is done and over. Facebook connection severed, not returning calls/text/email, all the same stuff. SM did NOT want a relationship, didn't want to commit to me or anyone else, insisted on dating other people, decided that our conversations had to become surface so I wouldn't 'stay' attached, towards the end he wanted to keep all chatting via email to make sure I understood he didn't want what "this" was turning into, all of the BS. It was bad bad bad. He said, he is a commitment phobe with attachment problems and he refused to hurt me. That he was protecting me from himself. I've basically broken up with him twice. We've gone month's without any communication. It's been 6 month's of going back and forth like this. I've cried myself to sleep many nights. As bad as things were, there is no one who has ever made me feel as loved and cherished. Crazy - right? SM connection.........
If you read about soul mate connections, this is all so typical. CSK has a good link to some interesting articles.
Force yourself to get out there and date. Maybe the universe will throw you 'someone' good. Because if and when SM comes back, you will probably have another bumpy ride.