I feel the same way sometimes. In fact, these past days I feel like asking my W to leave as a kind of ultimatum: either you love me, say so, and express it, or it is better that you move out.
Yet, if I look at my sitch objectively, I see that I (we) have made great progress. Many small babysteps add up over time. To confront my W like that would do the opposite of bring us together, and the only reason I feel that way is my frustration with how long this takes.
Back to your sitch, I think Michele's advice on setting small goals helps you keep things going. If you set small goals and see improvements, then it builds motivation for you to keep going. So you need to ask yourself, what are your small goals?
