I'm sorry to hear about your problems - your recognition of the seriousness of them is a big part of helping resolve them. I hope that you can find some of the help you need with the books, and through this board.
First question - have you done any marriage counseling? If not, try to get some right away. You mentioned a psych eval, but unless your R problems are driven by some traumatic event in your past, or you actually have a mental illness (dementia, etc.), a psych eval is unlikely to help you correct the problem.
About his unwillingness to let you touch him - as a HDH, I can tell you that this is almost certainly a defensive mechanism he is using to deal with the hurt of long-term rejection from you. He is afraid to allow you to touch him, because it could lead him to believe that you have recovered your affection for him - or maybe you haven't. The possibility of his being rejected again is more painful than preventing any contact in the first place, so he doesn't want you to touch him. Unless there is communication first, so that he understands where you are coming from, he won't open himself up to the possibility of being further hurt. That's one of the reasons why counseling is so important.
If the rest of your R is still good, it may not be to late to salvage it, but you need to act quickly. His telling you that he cannot take it any longer is the last tool he has to make you see and understand his pain & desperation.
