There may be many reasons for not wanting to be sexualy intimate.
Some are psychological ex depression and some physiological such as low testastorone.
There is help for both conditions. Below I have attached links to sex therapists and possible causes/treatment for low libido.
http://search.lef.org/cgi-src-DANGEROUS URL REMOVED?grab_id=0&page_id=1504&query=low%20libido&hiword=LIBIDOS%20libido%20low%20