Not happy in my relationship but, can't find it in me to end it?

Not happy for a reason. End it. It's rarely easy. Who knows, the feeling could easily be mutual. That makes it as easy as can be expected. Forcing it will only make it end even worse because of how you will eventually start treating them.

Sit down and make a list of all of the positive and negative things in your relationship. Go through all of the negative things and decide if any of them can be improved, removed or otherwise resolved. Then go about immediately dealing with those that are directly related to your behavior. If you can't at least change them then you might as well stay in the relationship because you'll just take them with you into a new relationship, along with your shadow! Knowing nothing at all about the dynamics between the two of you this all I've got to offer.

Try being apart for awhile.

If you love someone, set them free. If they come back they're yours; if they don't they never were