Separate your emotions from your logic. Talk to a family lawyer or a counsellor who will keep you rational and give you the strategy you need to either stay in the marriage or get out. Read this blog it is very helpful: http://www.ylaw.ca/blog-resources/best-vancouver-legal-advice-divorce-family-lawyers/
I am going to through a very similar situation. I see that you posted this a while ago and was wondering how it's going.
I have been with my husband almost half my life. 17 years but we just got married two years ago.
I've know from the beginning that we aren't meant for each other. We just so different. I love him and he is my best friend. But I know that we should have ended this so long ago, I thought getting married might stop all this uncertainty that he has but it didn't.
He moved in the the guest room for two weeks and then we were fighting and I told him that he needs to leave the house. He has been gone now for a week and a half.
I miss him and I can't figure out how to stay strong and get myself to move past this. Normally I would talk to him when I am going through something hard. I want to ask him to come back 17 years is a long time to just walk away from. But I know I can't.