You said you've just finished reading the SSM. What did you think about the "just do it" approach?
I can tell you from experience, that if you really do "just do it", and "just keep doing it", then over time your body will learn to relax and be happy about it. So that is question #1 - what did you think about that part of the book when you read it? Did your mind come up with "reasons" for being opposed to it?
Question #2 - do you have sexual fantasies? Even if they do not involved sex, but are just sexual? When you said you are not really sure what makes a "good" lover, does that apply to your fantasies as well? Or do you just not have any? Can you fantasize about a "good" sexual experience?
Question #3 - after 1.5 years of counseling, are you making progress that is demonstrated? Its great that you are feeling more comfortable naked, but has actual intercourse increased?
Question #4 - Now that you've read the book, do you realize how absolutely miserable you may be making your husband? Do you really "get it"?