I had something of a similar situation, and it's not a success story. But I think you're doing the right thing by going to therapy and learning how to communicate better.

About a year ago, my wife of 8 years finally brought to my attention that she was unhappy in the relationship. By the time she told me, though, it turned out she had been unhappy for a long time and suffering in silence – and I didn't have a clue. When she finally was able to articulate it, I tried to make changes, and we went to couples' therapy, but the changes didn't happen quickly enough for her. She was already emotionally drained when we started working on it, so she left me in fairly short order.

I've read that women are usually more attuned to the emotional health of relationships, and while that may be true, I really wish my wife had been more direct instead of hiding her feelings from me for so long. While I certainly have my faults, I think she had always been afraid of, or unable to expressing her emotions effectively, and I consider myself a fairly sensitive person.

Anyway, stay strong, and do this for yourself at least as much as for your wife. Also, have a look at "No More Mr. Nice Guy" and see how much of this applies to you.