Here's my background... I began dating a guy, GM, in May 2003.  In January 2005, I discovered he was talking to a girl he knew from before and she sent him a topless photo of herself, to which he saved on his computer.  After I confronted him about it, I decided to forgive him and try to make it work.  Things were going fine, and a little while later we moved into together. 

We had our ups and downs, mostly relating to our sex life.  His sex drive decreased dramatically, and it was affecting our relationship.  I encouraged him to seek out professional help, talk with a counselor, anything, but he never did.  Instead, after two years of having this problem, he decided to join an adult site that was all about hooking up with people.  He kept that from me for about a year until i discovered it in January.  He claims he was merely talking to other people about how to improve our sex life.  However, his profile on this site listed him as "single and looking for a discreet relationship."  His response to that is that he didn't think people would talk to him if he said he was in a relationship.  He admitted what he did was wrong, apologized and wanted to make it work.  I wanted so badly to believe him because we had after all, been dating for 4.5 years at that point and were in talks about marriage and buying a house.  After trying to work it out, I ended it in March.

Problem was I was still stuck in a lease with him until July and couldn't get out of it.  So, I lived with him as strictly roommates.  I began dating someone in April, and ended it with that person just two weeks after my lease with my ex was over.  The reason why I ended it with the new guy?  I didn't give myself time to grieve GM. I became so accostumed to seeing him everyday that when I no longer saw him, the grief hit me HARD.

Now, I'm staying with my mom (I'm 28) until I can get over my grief and be OK with living alone.  But I am simply NOT OK with it.  It's been months since it's been over with GM, but I'm still hurting badly.  I haven't been able to eat because my stomach is in knots.  A part of me wants him back and to go back to when things were good.  The other part of me says it's not worth it and he hurt me twice.

I'm so afraid of living alone it's unbearable for me to even think about it.  Depression, unfortunately, is something I've been dealing with since my teens.  I'm so afraid of it getting worse when I live by myself.  I've never lived by myself before.  I'm also not the most outgoing person, so I don't have a lot of friends to hang out with to make it less lonely.  I have been talking with a counselor, who is confident I can make living alone work.  But I'm not confident that I can do it.  I cry whenever I think about it.  It's affecting me so much, I don't know how to deal with it.

Advice needed, please!