I agree with catperson that 2012 is too long.
What I ended up doing (after I demanded that SD leave my home) was filing for divorce, because I need to secure my finances against his behaviour. Because I have the house, I went ahead and hired an attorney, but she's one of my BFF's so she let me pay her down a little more than the filing fees and I pay her monthly until the fee is paid.
Now, STBX isn't physically out of the house yet, because the only places he has to go are out of range of his long term sub job. So we've had to negotiate how he'll be in the house - in the "spare" room, contributing to the chores & such.
If the housemate situation wasn't working out well, I was going to give him a month's notice to get out.
What you need to remember is that he's an adult. You can have compassion, but he needs to be able to fend for himself. You're NOT his mother. You can tell him this is where it's going, that you're moving on X date, and he needs to figure out what he's going to do. You can ask for his input on how long it will take him to get self sufficient, but don't be held to it or he'll drag it out as long as possible.
As for your place on this forum, I'm in the same boat BUT I propose that we can determine that the CURRENT marriage isn't workable, and still be here because we're determined to figure out what went wrong (even if that's in the choice of partners) and how to make sure we do better next time.