Did she tell you what how you could do things differently?
Is she on antidepressants?
Is she on birth control?
Or any other medication?
Has her personality in general changed?
Is she more 'lazy' now than she used to be?
Did she actually show and or tell you how she wanted to be touched or did she only tell you what was wrong.
I take it this "coaching session" took place when you two were having sex? Being as objective as you can, was your reaction more an angry/defensive because you felt belittled by her tone and attitude, or because her tone and attitude clearly were over the line? IOW! Some people, not just men, can't handle being corrected at all. Might you be one of them? Or close to one of them?
Just to calm your feelings of inadequacy, you are not a mind reader and without feedback you can't possibly know exactly how she wants it. Some women give obvious body signals, sounds increased movement etc, to indicate positive feedback. Other women talk, yes, right there, softer/harder...etc. but if your wife was too subtle in the past, or worse yet was dishonest about being content with the way you typically touched her, you would never know.
Think of getting your back scratched. You have to give directions to get the right place taken care of. If giving the back scratch and your not getting directions you can assume that the general all over back scratch is what works. But if that's not what the recipient wants or needs, they must give feedback.
Why does your wife think she is unattractive if she is in shape as she has always been? Has she in the past said things indicating a poor self image or is this new?